Data collection system, data collection method and data collection program

ABSTRACT

It is an object to provide a data collection system that is configured to reduce a communication amount, etc. at the time when data are collected from devices, so as to reduce a communication amount attended by the collection of data without increasing processing loads imposed on devices. The data collecting device comprises a code operating means for deriving a frequency of the symbol for each symbol corresponding to the code being contained in the already compressed data based upon the data analysis result being contained in the received already compressed data, and a code operation developing means for adding the frequency of the description format, out of the frequencies obtained by the code operating means, to the frequency of the basic symbol corresponding to the above description format, and adding the frequency of the derivative symbol to the frequency of each basic symbol constituting the derivative symbol.

REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No.12/528,587 filed Aug. 25, 2009 and claims the benefit of its priority.

APPLICABLE FIELD IN THE INDUSTRY

The present invention relates to a data collection system for collectingdata via a communication network and a data collection method as well asa data relaying device, a transfer destination information updatingdevice, a data collecting device, a data relaying program, a transferdestination information update program, and a data collection programeach of which is applied for the data collection system, and moreparticularly to a data collection system for classifying communicationdata by employing a statistical special feature of the data in somecases, recompressing the data by employing an analysis result of thedata in a compressing process in some cases, and further, operating thecompressed data by employing the analysis result of the data in thecompressing process in some cases, and a data collection method as wellas a data relaying device, a transfer destination information updatingdevice, a data collecting device, a data relay program, a transferdestination information update program, and a data collection programeach of which is applied for the data collection system.

BACKGROUND ART

As an example of a system for collecting data via a communicationnetwork, the data collection system for collecting the data from aplurality of RFID (Radio Frequency Identification) readers can belisted. Further, there exists the system for collecting information ofprobe cars in GPS (Global Positioning System) or ITS (IntelligentTransport System), the system for collecting operational information oncommunication appliances and facilities of a power system via acommunication network from a plurality of devices, or the like.Additionally, the probe car is a vehicle capable of acquiring andtransmitting position information and speed information. Thecommunication data compression technique that is employed in such a datacollection system is a technique of compressing data communication pathby communication path.

In Patent document 1, the data transfer method of compressingcommunication data and transferring it to a server has been disclosed.In the data transfer method disclosed in the Patent document 1, a clientcompresses data, and in addition, divides it for each specified size.The client transmits divided files one file by one file to the server,and the server couples and defrosts a plurality of pieces of thereceived data.

Further, in Patent document 2, the equipment control system providedwith an equipment controlling means for receiving equipment registrationvia a home network communicating means has been disclosed. Further, inPatent document 3, the data transfer method has been disclosed ofdeciding a transfer destination of data responding to a genre code whenhaving received data including the genre code.

-   Patent document 1: JP-P2005-011119A (paragraphs 0019 to 0028)-   Patent document 2: JP-P2005-310022A (paragraph 0015)

Patent document 3: JP-P2006-228201A (paragraph 0018)

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Conventionally, collecting data from a plurality of appliances has ledto a decline in a compression ratio of the data because the data iscompressed communication path by communication path, and as a result, acommunication time required for data collection has been lengthened.

Further, the compressed data is recompressed in some cases in order tocurtail a communication amount attended by the collection at the momentof collecting data from a plurality of appliances. At this time, onlyrecompressing a plurality of pieces of the compressed data together in asimplified manner does not yield the sufficient compression. For this,as a rule, after expanding the compressed data and coupling a pluralityof pieces of the expanded data into one piece of the data, the abovedata is compressed, thereby allowing the data to be recompressed.However, the process of, after expanding each compressed data to theoriginal data, and coupling the above data, compressing it once againcauses the processing load to be increased. That is, there is a problemthat recompressing the data for a purpose of curtailing thecommunication amount causes the processing load to be increased.

Further, the data collecting device for collecting the data from aplurality of devices, as a rule, operates the collected data. At thistime, the load imposed upon the data collecting device is raised becauseit expands the collected compressed data to the original data, andoperates the after-expansion data.

Thereupon, the present invention has an object of reducing thecommunication amount at the moment of collecting the data from aplurality of the appliances. Further, the present invention has anobject of making a speed of the recompressing process at the moment offurthermore recompressing the compressed data being collected fast.Further, the present invention has an object of enhancing a speed of thecollecting process of the data and a speed of the operating process ofthe collected data.

Means to Solve the Problem

The data collection system of the present invention, which includes aplurality of data compressing devices for compressing data, a pluralityof data relaying devices for relaying the data, and a data collectingdevice for collecting the data, is characterized in that: the datarelaying device includes: a data analysis result synthesizing means forderiving a new data analysis result from a data analysis result beingcontained in the received already compressed data; a data conversioninformation preparing means for generating new data conversioninformation indicative of a correspondence relation between a symbol anda new code responding to the foregoing new data analysis result; and adata converting means for converting the codes being contained in thealready compressed data into the new codes being contained in theforegoing new data conversion information so as to recompress the data,and generating the already compressed data containing the foregoing newcode, the new data conversion information, and the after-recompressioncode; and the data relaying devices are arranged hierarchy by hierarchyresponding to the number of hops or a round trip time up to the datacollecting device so that the smaller the number of the hops or theround trip time of the data relaying device up to the data collectingdevice is, the higher the hierarchy of the data relaying device becomes.

Further, the data collection system of the present invention, whichincludes a plurality of data compressing devices for compressing data, aplurality of data relaying devices for relaying the data, and a datacollecting device for collecting the data, is characterized in that: thedata relaying devices are arranged hierarchy by hierarchy responding tothe number of hops or a round trip time up to the data collecting deviceso that the smaller the number of the hops or the round trip time of thedata relaying device up to the data collecting device is, the higher thehierarchy of the data relaying device becomes; the data compressingdevice includes: a data compressing means for deriving the data analysisresult, being an analysis result of a statistical special feature of thedata that is a target of compression, converting the symbol, being abefore-compression bit string, into the code, being an after-compressionbit string, responding to the analysis result so as to compress thedata, and generating the already compressed data containing the dataconversion information indicative of a correspondence between the symboland the code, the code, and the data analysis result; and acommunicating means (for example, a communicating means 31) fortransmitting the already compressed data to the data relaying devices ofa lowest-place hierarchy; the data relaying device includes: a dataanalysis result synthesizing means for deriving a new data analysisresult from the data analysis result being contained in each of piecesof the received already compressed data; a data conversion informationpreparing means for generating new data conversion informationindicative of a correspondence relation between the symbol and the newcode responding to the foregoing new data analysis result; and a dataconverting means for converting the codes being contained in the alreadycompressed data into the new codes being contained in the foregoing newdata conversion information so as to recompress the data, and generatingthe already compressed data containing the foregoing new code, the newdata conversion information, the after-recompression code; the datarelaying devices of a highest-place hierarchy transmit the alreadycompressed data to the data collecting device; and the data relayingdevices except the data relaying devices of the highest-place hierarchytransmit the already compressed data to the data relaying devices thatrank higher by one hierarchy.

Further, the data collection system of the present invention forincluding a plurality of data compressing devices for compressing data,a plurality of data relaying devices for relaying the data, and a datacollecting device for collecting the data, in which the data relayingdevices are arranged hierarchy by hierarchy responding to the number ofhops or a round trip time up to the data collecting device so that thesmaller the number of the hops or the round trip time of the datarelaying device up to the data collecting device is, the higher thehierarchy of the data relaying device becomes, and each data relayingdevice receives already compressed data containing the data analysisresult, being an analysis result of a statistical special feature of thedata that is a target of compression, a code that is decided for asymbol, being a before-compression bit string, responding to theanalysis result, and data conversion information indicative of acorrespondence between the symbol and the code from the devices thatrank lower by one hierarchy, and transmits the new already compresseddata to the devices that rank higher by one hierarchy, is characterizedin that the data relaying device includes; a transfer destinationinformation recording means for storing transfer destination informationin which a symbol aggregation decided for each device that ranks higherby one hierarchy, being a transfer destination of the already compresseddata, and destination information of the foregoing device that rankshigher by one hierarchy have been caused to correspond to each other; asymbol classifying means for classifying the already compressed datareceived from the devices that rank lower by one hierarchy based uponthe symbol aggregation being contained in the transfer destinationinformation; a data analysis result synthesizing means for deriving anew data analysis result symbol aggregation by symbol aggregation fromthe data analysis result being contained in each of pieces of thereceived already compressed data; a data conversion informationpreparing means for generating new data conversion informationindicative of a correspondence relation between the symbol and the newcode symbol aggregation by symbol aggregation responding to theforegoing new data analysis result; and a data converting means forconverting the codes being contained in the already compressed data intothe new codes being contained in the foregoing new data conversioninformation so as to recompress the data, and generating the alreadycompressed data containing the foregoing new code, the new dataconversion information, and the after-recompression code.

The data collection system of the present invention may be configured sothat: it includes a transfer destination information updating device forupdating the transfer destination information of the data relayingdevices of each hierarchy; and the transfer destination informationupdating device includes: a data relaying device information recordingmeans for storing data relaying device information in whichidentification information of the data relaying device and thedestination information have been caused to correspond to each other foreach data relaying device; a receiving means (for example, acommunicating means 51) for receiving the identification information ofthe data relaying device, a communication speed at the moment that thedata relaying device transmits the already compressed data to thedevices that rank higher by one hierarchy, a processing speed at thetime of recompression, and a frequency table, being informationindicative of a frequency of each symbol corresponding to the code beingcontained in the already compressed data from the data relaying devicesof each hierarchy; a symbol distribution generating means forsynthesizing the frequency tables received from each data relayingdevice of the identical hierarchy into one frequency table; a symbolcluster information generating means (for example, a symbol aggregationclustering means 54) for generating symbol cluster information in whicha hierarchy number indicative of the hierarchy, the symbol aggregation,and the data relaying device identification information have been causedto correspond to each other based upon the frequency table synthesizedby the symbol distribution generating means, the identificationinformation of the data relaying device, the communication speed and theprocessing speed; and a transfer destination information generatingmeans for generating transfer destination information of each hierarchfrom the symbol cluster information and the data relaying deviceinformation.

Further, the data collection system of the present invention including aplurality of data compressing devices for compressing data, a pluralityof data relaying devices for relaying the data, and a data collectingdevice for collecting the data, in which the data relaying devices arearranged hierarchy by hierarchy responding to the number of hops or around trip time up to the data collecting device so that the smaller thenumber of the hops or the round trip time of the data relaying device upto the data collecting device is, the higher the hierarchy of the datarelaying device becomes, and the data collecting device receives thealready compressed data containing a data analysis result, being ananalysis result of a statistical special feature of the data that is atarget of compression, a code that is decided for a symbol, being abefore-compression bit string, responding to the analysis result, anddata conversion information indicative of a correspondence between thesymbol and the code from each relaying device of a highest-placehierarchy, is characterized in that the data collecting device includes;a basic symbol description format recording means for storing symboldescription information in which a basic symbol, being a symbol dividedinto a minimum unit, and a description format in which the basic symbolhas been expressed with other formats have been caused to correspond toeach other; a derivative symbol format recording means for storinginformation in which a derivative symbol, being a symbol in which thebasic symbols have been combined, and an aggregation of the basicsymbols constituting the derivative symbol have been caused tocorrespond to each other; a code operating means for deriving afrequency of the symbol for each symbol that corresponds to the codebeing contained in the already compressed data based upon the dataanalysis result being contained in each of pieces of the receivedalready compressed data; and a code operation developing means foradding the frequency of the description format, out of the frequenciesobtained by the code operating means, to the frequency of the basicsymbol that corresponds to the above description format, and adding thefrequency of the derivative symbol to the frequency of each basic symbolconstituting the derivative symbol.

Further, the data collection method of the present invention, which isapplied for a data collection system including: a plurality of datacompressing devices for compressing data; a data collecting device forcollecting the data: and data relaying devices that are arrangedhierarchy by hierarchy responding to the number of hops or a round triptime up to the data collecting device so that the smaller the number ofthe hops or the round trip time of the data relaying device up to thedata collecting device is, the higher the hierarchy of the data relayingdevice becomes, is characterized in that: the data relaying devicederives a new data analysis result from a data analysis result beingcontained in each of pieces of the received already compressed data; thedata relaying device generates new data conversion informationindicative of a correspondence relation between a symbol and a new coderesponding to the foregoing new data analysis result; the data relayingdevice converts the codes being contained in the already compressed datainto the new codes being contained in the foregoing new data conversioninformation so as recompress the data, and generates the alreadycompressed data containing the foregoing new code, the new dataconversion information, and the after-recompression code; and the datarelaying devices transmits the already compressed data to the devicesthat rank higher by one hierarchy.

Further, the data collection method of the present invention, which isapplied for a data collection system including: a plurality of datacompressing devices for compressing data; a data collecting device forcollecting the data; and data relaying devices that are arrangedhierarchy by hierarchy responding to the number of hops or a round triptime up to the data collecting device so that the smaller the number ofthe hops or the round trip time of the data relaying device up to thedata collecting device is, the higher the hierarchy of the data relayingdevice becomes, is characterized in that: the data compressing devicederives the data analysis result, being an analysis result of astatistical special feature of the data that is a target of compression,converts the symbol, being a before-compression bit string, into thecode, being an after-compression bit string, responding to the analysisresult so as to compress the data, and generates the already compresseddata containing the data conversion information indicative of acorrespondence between the symbol and the code, the code, and the dataanalysis result; the data compressing device transmits the alreadycompressed data to the data relaying devices of a lowest-placehierarchy; the data relaying device derives a new data analysis resultfrom the data analysis result being contained in each of pieces of thereceived already compressed data; the data relaying device generates newdata conversion information indicative of a correspondence relationbetween the symbol and the new code responding to the foregoing new dataanalysis result; the data relaying device converts the codes beingcontained in the already compressed data into the new codes beingcontained in the foregoing new data conversion information so as torecompress the data, and generating the already compressed datacontaining the foregoing new code, the new data conversion information,the after-recompression code; the data relaying devices of thehighest-place hierarchy transmit the already compressed data to the datacollecting device; and the data relaying devices except the datarelaying devices of the highest-place hierarchy transmit the alreadycompressed data to the data relaying devices that rank higher by onehierarchy.

Further, the data collection method of the present invention, which isapplied for a data collection system including: a plurality of datacompressing devices for compressing data; a data collecting device forcollecting the data; and data relaying devices that are arrangedhierarchy by hierarchy responding to the number of hops or a round triptime up to the data collecting device so that the smaller the number ofthe hops or the round trip time of the data relaying device up to thedata collecting device is, the higher the hierarchy of the data relayingdevice becomes, is characterized in that: the data relaying devicepre-stores transfer destination information in which a symbolaggregation decided for each device that ranks higher by one hierarchy,being a transfer destination of the already compressed data, anddestination information of the foregoing device that ranks higher by onehierarchy have been caused to correspond to each other; the datarelaying device receives the already compressed data containing the dataanalysis result, being an analysis result of a statistical specialfeature of the data that is a target of compression, the code that isdecided for the symbol, being a before-compression bit string,responding to the analysis result, and data conversion informationindicative of a correspondence between the symbol and the code from thedevices that rank lower by one hierarchy; the data relaying deviceclassifies the already compressed data received from the devices thatrank lower by one hierarchy, based upon the symbol aggregation beingcontained in the transfer destination information; the data relayingdevice derives a new data analysis result symbol aggregation by symbolaggregation from the data analysis result being contained in each ofpieces of the received already compressed data; the data relaying devicegenerates new data conversion information indicative of a correspondencerelation between the symbol and the new code symbol aggregation bysymbol aggregation responding to the foregoing new data analysis result;the data relaying device converts the codes being contained in thealready compressed data into the new codes being contained in theforegoing new data conversion information so as to recompress the data,and generates the already compressed data containing the foregoing newcode, the new data conversion information, and the after-recompressioncode; and the data relaying device transmits the already compressed datato the devices that rank higher by one hierarchy.

Further, the data collection method of the present invention, which isapplied for a data collection system including: a plurality of datacompressing devices for compressing data; a data collecting device forcollecting the data, which receives already compressed data containing adata analysis result, being an analysis result of a statistical specialfeature of the data that is a target of compression, a code that isdecided for a symbol, being a before-compression bit string, respondingto the analysis result, and data conversion information indicative of acorrespondence between the symbol and the code from each relaying deviceof a highest-place hierarchy; and data relaying devices, which arearranged hierarchy by hierarchy responding to the number of hops or around trip time up to the data collecting device so that the smaller thenumber of the hops or the round trip time of the data relaying device upto the data collecting device is, the higher the hierarchy of the datarelaying device becomes, is characterized in that: the data collectingdevice stores symbol description information in which a basic symbol,being a symbol divided into a minimum unit, and a description format inwhich the basic symbol has been expressed with other formats have beencaused to correspond to each other; the data collecting device storesinformation in which a derivative symbol, being a symbol in which thebasic symbols have been combined, and an aggregation of the basicsymbols constituting the derivative symbol have been caused tocorrespond to each other; the data collecting device derives a frequencyof the symbol for each symbol that corresponds to the code beingcontained in the already compressed data, based upon the data analysisresult being contained in the received already compressed data; and thedata collecting device adds the frequency of the description format, outof the frequencies, to the frequency of the basic symbol thatcorresponds to the above description format, and adds the frequency ofthe derivative symbol to the frequency of each basic symbol constitutingthe derivative symbol.

Further, the data relaying device of the present invention for receivingalready compressed data containing a data analysis result, being ananalysis result of a statistical special feature of the data that is atarget of compression, a code that is decided for a symbol, being abefore-compression bit string, responding to the analysis result, anddata conversion information indicative of a correspondence between thesymbol and the code, which is applied for a data collection systemincluding: a plurality of data compressing devices for compressing data;a data collecting device for collecting the data; and data relayingdevices that are arranged hierarchy by hierarchy responding to thenumber of hops or a round trip time up to the data collecting device sothat the smaller the number of the hops or the round trip time of thedata relaying device up to the data collecting device is, the higher thehierarchy of the data relaying device becomes, is characterized inincluding: a data analysis result synthesizing means for deriving a newdata analysis result from the data analysis result being contained ineach of pieces of the received already compressed data; a dataconversion information preparing means for generating new dataconversion information indicative of a correspondence relation betweenthe symbol and the new code responding to the foregoing new dataanalysis result; and a data converting means for converting the codesbeing contained in the already compressed data into the new codes beingcontained in the foregoing new data conversion information so as torecompress the data, and generating the already compressed datacontaining the foregoing new code, the new data conversion information,and the after-recompression code.

Further, the transfer destination information updating device of thepresent invention for updating transfer destination information in whicha symbol aggregation decided for each device that ranks higher by onehierarchy, being a transfer destination of already compressed data, anddestination information of the foregoing device ranking higher by onehierarchy have been caused to correspond to each other, which is storedby data relaying devices being arranged hierarchy by hierarchyresponding to the number of hops or a round trip time up to a datacollecting device so that the smaller the number of the hops or theround trip time of the data relaying device up to a predetermined deviceis, the higher the hierarchy of the data relaying device becomes, ischaracterized in including: a data relaying device information recordingmeans for storing data relaying device information in whichidentification information of the data relaying device and thedestination information have been caused to correspond to each other foreach data relaying device; a receiving means (for example, acommunicating means 51) for receiving the identification information ofthe data relaying device, a communication speed at the moment that thedata relaying device transmits the already compressed data to thedevices that rank higher by one hierarchy, a processing speed at thetime of recompression, and a frequency table, being informationindicative of a frequency of each symbol corresponding to the code beingcontained in the already compressed data from the data relaying devicesof each hierarchy; a symbol distribution generating means forsynthesizing the frequency tables received from each data relayingdevice of the identical hierarchy into one frequency table; a symbolcluster information generating means (for example, a symbol aggregationclustering means 54) for generating symbol cluster information in whicha hierarchy number indicative of the hierarchy, the symbol aggregation,and the data relaying device identification information have been causedto correspond to each other based upon the frequency table synthesizedby the symbol distribution generating means, the identificationinformation of the data relaying device, the communication speed and theprocessing speed; and a transfer destination information generatingmeans for generating the transfer destination information of eachhierarch from the symbol cluster information and the data relayingdevice information.

Further, the data collecting device of the present invention, whichcollects already compressed data containing a data analysis result,being an analysis result of a statistical special feature of data thatis a target of compression, a code that is decided for a symbol, being abefore-compression bit string, responding to the analysis result, anddata conversion information indicative of a correspondence between thesymbol and the code, is characterized in including: a basic symboldescription format recording means for storing symbol descriptioninformation in which a basic symbol, being a symbol divided into aminimum unit, and a description format in which the basic symbol hasbeen expressed with other formats have been caused to correspond to eachother; a derivative symbol format recording means for storinginformation in which a derivative symbol, being a symbol in which thebasic symbols have been combined, and an aggregation of the basicsymbols constituting the derivative symbol have been caused tocorrespond to each other; a code operating means for deriving afrequency of the symbol for each symbol that corresponds to the codebeing contained in the already compressed data based upon the dataanalysis result being contained in the received already compressed data;and a code operation developing means for adding the frequency of thedescription format, out of the frequencies obtained by the codeoperating means, to the frequency of the basic symbol corresponding tothe above description format, and adding the frequency of the derivativesymbol to the frequency of each basic symbol constituting the derivativesymbol.

Further, the data relay program of the present invention, which isinstalled into a computer for receiving already compressed datacontaining a data analysis result, being an analysis result of astatistical special feature of data that is a target of compression, acode that is decided for a symbol, being a before-compression bitstring, responding to the analysis result, and data conversioninformation indicative of a correspondence between the symbol and thecode, generating new already compressed data, and relaying it to otherdevices, is characterized in causing the computer to execute: a dataanalysis result synthesizing process of deriving a new data analysisresult from the data analysis result being contained in each of piecesof the received already compressed data; a data conversion informationpreparing process of generating new data conversion informationindicative of a correspondence relation between the symbol and the newcode responding to the foregoing new data analysis result; and a dataconverting process of converting the codes being contained in thealready compressed data into the new codes being contained in theforegoing new data conversion information so as to recompress the data,and generating the already compressed data containing the foregoing newcode, the new data conversion information, and the after-recompressioncode.

Further, the transfer destination information update program of thepresent invention, which is installed into a computer including a datarelaying device information recording means for updating transferdestination information in which a symbol aggregation decided for eachdevice that ranks higher by one hierarchy, being a transfer destinationof already compressed data, and destination information of the foregoingdevice ranking higher by one hierarchy have been caused to correspond toeach other, which is stored by data relaying devices being arrangedhierarchy by hierarchy responding to the number of hops or a round triptime up to a data collecting device so that the smaller the number ofthe hops or the round trip time of the data relaying device up to apredetermined device is, the higher the hierarchy of the data relayingdevice becomes, and storing data relaying device information in whichidentification information of the data relaying device and thedestination information have been caused to correspond to each other foreach data relaying device, is characterized in causing the foregoingcomputer to execute: a receiving process of receiving the identificationinformation of the data relaying device, a communication speed at themoment that the data relaying device transmits the already compresseddata to the devices that rank higher by one hierarchy, a processingspeed at the time of recompression, and a frequency table, beinginformation indicative of a frequency of each symbol corresponding tothe code being contained in the already compressed data from the datarelaying devices of each hierarchy; a symbol distribution generatingprocess of synthesizing the frequency tables received from each datarelaying device of the identical hierarchy into one frequency table; asymbol cluster information generating process of generating symbolcluster information in which a hierarchy number indicative of thehierarchy, the symbol aggregation, and the data relaying deviceidentification information have been caused to correspond to each otherbased upon the frequency table synthesized in the symbol distributiongenerating process, the identification information of the data relayingdevice, and the communication speed and the processing speed; and atransfer destination information generating process of generating thetransfer destination information of each hierarch from the symbolcluster information and the data relaying device information.

Further, the data collection program of the present invention ischaracterized in causing a computer including: a basic symboldescription format recording means for collecting already compresseddata containing a data analysis result, being an analysis result of astatistical special feature of data that is a target of compression, acode that is decided for a symbol, being a before-compression bitstring, responding to the analysis result, and data conversioninformation indicative of a correspondence between the symbol and thecode, and storing symbol description information in which a basicsymbol, being a symbol divided into a minimum unit, and a descriptionformat in which the basic symbol has been expressed with other formatshave been caused to correspond to each other; and a derivative symbolformat recording means for storing information in which a derivativesymbol, being a symbol in which the basic symbols have been combined,and an aggregation of the basic symbols constituting the derivativesymbol have been caused to correspond to each other to execute: a codeoperating process of deriving a frequency of the symbol for each symbolcorresponding to the code being contained in the already compresseddata, based upon the data analysis result being contained in thereceived already compressed data; and a code operation developingprocess of adding the frequency of the description format, out of thefrequencies obtained in the code operating process, to the frequency ofthe basic symbol corresponding to the above description format, andadding the frequency of the derivative symbol to the frequency of eachbasic symbol constituting the derivative symbol.

An Advantageous Effect of the Invention

The present invention makes it possible to curtail the processing load,which is imposed upon the device for performing the compressing processat the moment of compressing the data with the communicating device overa communication path for a purpose of curtailing the communicationamount attended by the collection of the data from a plurality of theappliances because the data relaying device includes the data convertingmeans for converting the codes being contained in the already compresseddata into the new codes being contained in the new data conversioninformation so as to recompress the data, and generating the alreadycompressed data containing the new code, the new data conversioninformation, the after-recompression code.

Further, the present invention makes it possible to shorten thecommunication time at the moment of collecting the data from a pluralityof the appliances because the data relaying device includes: thetransfer destination information recording means for storing thetransfer destination information in which the symbol aggregation decidedfor each device that ranks higher by one hierarchy, being a transferdestination of the already compressed data, and the destinationinformation of the device that ranks higher by one hierarchy have beencaused to correspond to each other; the symbol classifying means forclassifying the already compressed data received from the devices thatrank lower by one hierarchy based upon the symbol aggregation beingcontained in the transfer destination information; the data analysisresult synthesizing means for deriving the new data analysis resultsymbol aggregation by symbol aggregation from the data analysis resultbeing contained in each of pieces of the received already compresseddata; the data conversion information preparing means for generating thenew data conversion information indicative of a correspondence relationbetween the symbol and the new code symbol aggregation by symbolaggregation responding to the above new data analysis result; and thedata converting means for converting the codes being contained in thealready compressed data into the new codes being contained in the abovenew data conversion information so as to recompress the data, andgenerating the already compressed data containing the above new code,the new data conversion information, and the after-recompression code.

Further, the present invention makes it possible to suppress an increasein the operation processing load imposed upon the data collecting devicebecause the data collecting device includes the code operating means forderiving a frequency of the symbol for each symbol that corresponds tothe code being contained in the already compressed data based upon thedata analysis result being contained in the received already compresseddata; and the code operation developing means for adding the frequencyof the description format, out of the frequencies obtained by the codeoperating means, to the frequency of the basic symbol that correspondsto the above description format, and adding the frequency of thederivative symbol to the frequency of each basic symbol constituting thederivative symbol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view illustrating a configuration example ofthe data collection system of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of thedata compressing device.

FIG. 3 is a block diagram illustrating a configuration example of thedata relaying device.

FIG. 4 is a block diagram illustrating the symbol aggregation clusteringinformation acquiring means.

FIG. 5 is a block diagram illustrating the data recompressing means.

FIG. 6 is a block diagram illustrating a configuration example of thedata collecting device.

FIG. 7 is a block diagram illustrating a configuration example of thetransfer destination information updating device.

FIG. 8 is a flowchart illustrating an example of an operation of thedata collection system of the present invention.

FIG. 9 is a flowchart illustrating an example of an operation of thedata compressing device.

FIG. 10 is a flowchart illustrating an example of an operation of thedata relaying device.

FIG. 11 is a flowchart illustrating an example of an operation of thedata relaying device.

FIG. 12 is a flowchart illustrating an example of an operation of therecompressing means.

FIG. 13 is a flowchart illustrating an example of an operation of thedata collecting device.

FIG. 14 is a flowchart illustrating an example of an operation of thedata collecting device.

FIG. 15 is a flowchart illustrating an example of an operation of thesymbol aggregation clustering information collecting means.

FIG. 16 is a flowchart illustrating an example of an operation of thesymbol aggregation clustering information collecting means.

FIG. 17 is an explanatory view illustrating an example of an operationof the transfer destination information updating device.

FIG. 18 is a flowchart illustrating an example of an operation ofgenerating the symbol cluster information.

FIG. 19 is an explanatory view illustrating an example of an alreadysorted frequency list.

FIG. 20 is an explanatory view illustrating an example of an alreadysorted data relaying device list.

FIG. 21 is an explanatory view illustrating an example of a first-orderdifferential value list.

FIG. 22 is an explanatory view illustrating an example of a second-orderdifferential value list.

FIG. 23 is an explanatory view illustrating one example of an inflectionpoint list.

FIG. 24 is an explanatory view illustrating an example of data beinggenerated by each data generating device.

FIG. 25 is an explanatory view illustrating an example of dictionarydata.

FIG. 26 is an explanatory view illustrating an example of the dataanalysis result and the data conversion information.

FIG. 27 is an explanatory view illustrating an example of the dataanalysis result and the data conversion information generated by aplurality of the data compressing devices.

FIG. 28 is an explanatory view illustrating an example of the transferdestination information.

FIG. 29 is an explanatory view illustrating an example of generating onedata analysis result from a plurality of the data analysis results.

FIG. 30 is an explanatory view illustrating an example of the dataconversion information.

FIG. 31 is an explanatory view illustrating an example of therecompression.

FIG. 32 is an explanatory view illustrating an example of the dataanalysis result.

FIG. 33 is an explanatory view illustrating an example of the symboldescription information.

FIG. 34 is an explanatory view illustrating an example of the derivativesymbol configuration information.

FIG. 35 is an explanatory view illustrating an example of the frequencytable.

FIG. 36 is an explanatory view illustrating an example of a histogram.

FIG. 37 is an explanatory view illustrating an example of the executionhistory information.

FIG. 38 is an explanatory view illustrating an example of the frequencytable of the symbol.

FIG. 39 is an explanatory view illustrating an example of thecommunication speed, the processing speed, the hierarchy number, and thedata relaying device identification information that the transferdestination information updating device receives.

FIG. 40 is an explanatory view illustrating an example of the frequencytable obtained by adding a total of the by-symbol numbers of times ofappearances.

FIG. 41 is an explanatory view illustrating an example of the symbolcluster information.

FIG. 42 is an explanatory view illustrating an example of the datarelaying device information.

DESCRIPTION OF NUMERALS

-   -   1 to N5 data compressing devices    -   1′ to N5′ data generating devices    -   1,1 to 3,5 data relaying devices    -   5 transfer destination information updating device    -   7 data collecting device    -   11 communicating means    -   12 received data recording means    -   13 data analysis result acquiring means    -   14 code operating means    -   15 basic symbol description format recording means    -   16 code operation developing means    -   17 derivative symbol description format recording means    -   18 operation result recording means    -   41 communicating means    -   42 received data recording means    -   43 symbol classifying means    -   44 data recompressing means    -   45 transfer destination information recording means    -   46 transfer destination deciding means    -   47 symbol aggregation clustering information acquiring means    -   51 communicating means    -   52 distance parameter acquiring means    -   53 symbol distribution generating means    -   54 symbol aggregation clustering means    -   55 transfer destination information generating means    -   56 data relaying device information recording means

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be explained bymaking a reference to the accompanied drawings.

FIG. 1 is an explanatory view illustrating a configuration example ofthe data collection system of the present invention. The data collectionsystem shown in FIG. 1 includes data generating devices 1′ to N5′ forgenerating the data, being an arbitrary bit string, data compressingdevices 1 to N5 for collecting the data generated by the data generatingdevice for a constant time, and compressing it, a data collecting device7 for collecting the data, a plurality of data relaying devices (a datarelaying devices 1,1 to data relaying devices K,J), and a transferdestination information updating device 5 (not shown in FIG. 1. See FIG.7). The data relaying device receives the compressed data from the datacompressing device or the other data relaying devices, recompresses thecompressed data, and transfers the after-recompression data to otherrelaying devices or the data collecting device 7. The data relayingdevice stores (records) the transfer destination information fordeciding the data relaying device, being a transfer destination of therecompressed data. The transfer destination information updating device5 updates the transfer destination information stored in each datarelaying device.

Each of the data relaying devices (the data relaying devices 1,1 to thedata relaying devices K,J) is arranged over a communication network suchas Internet constructed between each of the data generating devices 1′to N5′ and the data collecting device 7. A hierarchy number is allottedto each of the data relaying devices (the data relaying devices 1,1 tothe data relaying devices K,J). In the explanation of this embodiment,“X” in the inscription of “the data relaying device X,Y” signifies thehierarchy number. The number of the communicating devices through whicha certain communicating device makes communication with anothercommunicating device is called the number of hops. Further, the time inwhich a packet makes a round trip between a certain communicating deviceand another communicating device is called a round trip time. Theso-called data relaying device belonging to the identical hierarchy is adata relaying device of which the number of the hops (the round triptime may be employed) at the time of making communication with the datacollecting device 7 is identical, and the identical hierarchy number isallotted to the data relaying device belonging to the identicalhierarchy. For example, the data relaying device 1,1 and the datarelaying device 1,2 shown in FIG. 1, which are identical to each otherin the number of the hops at the time of making communication with thedata collecting device 7, belong to the common first hierarchy. “Y” inthe inscription of “the data relaying device X,Y” is a number allottedto each data relaying device belonging to the identical hierarchy.

Further, it is assumed that the larger the number of the hops at thetime of making communication with the data collecting device 7 is, thelarger the hierarchy number becomes. Each data relaying device receivesthe data from the data relaying devices of which the hierarchy number islarger by one (1). Further, the data relaying devices of which thehierarchy number is largest receives the data from the data compressingdevice. The data relaying devices of which the hierarchy number is one(1) transmit the data received from the data relaying devices of whichthe hierarchy number is larger by one (the data relaying devices ofwhich the hierarchy number is two (2)) to the data collecting device 7.Further, each data relaying device recompresses the receivedcompressed-data, and transmits it to the other data relaying devices orthe data collecting device 7.

In the following explanation, a plurality of the data relaying devicesof which the hierarchy number is smaller by one (1) than that of acertain data relaying device are referred to as an upper-place datarelaying device group, and a plurality of the data relaying devices ofwhich the hierarchy number is larger by one (1) are referred to as alow-place data relaying device group.

Individual data generating devices P′ (P′=1′ to N5′ in an example shownin FIG. 1) make communication with the corresponding data compressingdevices P (P=1 to N5 in an example shown in FIG. 1), respectively. Forexample, the data generating device 1′ transmits the data to the datacompressing device 1.

Each of the data compressing devices 1 to N5 receives the data from thecorresponding data generating device. And, it compresses the receiveddata, and transmits the compressed data to one of the data relayingdevices of the lowest-place hierarchy (the data relaying devices havingthe hierarchy number 3 in an example shown in FIG. 1).

In an example shown in FIG. 1, the hierarchy number of the data relayingdevice is three. And, the data collecting system includes two devices,i.e. the data relaying device 1,1 and the data relaying device 1,2 as adata relaying device having the hierarchy number 1. Further, it includesthree devices, i.e. the data relaying device 2,1 to the data relayingdevice 2,3 as a data relaying device having the hierarchy number 2, andfive devices, i.e. the data relaying device 3,1 to the data relayingdevice 3,5 as a data relaying device having the hierarchy number 3.Further, an example shown in FIG. 1 shows the case that the datarelaying device 3,1 makes communication with the data compressingdevices 1 to N1, the data relaying device 3,2 makes communication withthe data compressing devices N1+1 to N2, the data relaying device 3,3makes communication with the data compressing devices N2+1 to N3, thedata relaying device 3,4 makes communication with the data compressingdevices N3+1 to N4, and the data relaying device 3,5 makes communicationwith the data compressing devices N4+1 to N5.

In addition, FIG. 1 shows the case that the data compressing device P(P=1 to N5) is connected to the data generating device P′ (P′=1′ to N5′)one versus one, and receives the data from the data generating device towhich a connection has been made. It is assumed that the codes shown inFIG. 1, i.e. N1, N2, N3, N4, and N5 are natural numbers, and N1>1,N2>N1+1, N3>N2+1, N4>N3+1, and N5>N4+1.

FIG. 2 is a block diagram illustrating a configuration example of thedata compressing device. Each of the data compressing devices 1 to N5includes a communicating unit 31, a received data recording unit 34, adata compressing unit 32, and a symbol dictionary recording unit 33.FIG. 2 shows the data compressing device 1, out of the data compressingdevices 1 to N5 shown in FIG. 1, which are similar to each other in theconfiguration.

The communicating unit 31 is a device for transmitting/receiving thedata such as Ethernet (Registration Trademark). The communicating unit31 receives the data from one data generating device and transmits thedata to a plurality of the data relaying devices.

The received data recording unit 34 is a storing device for recordingthe data received from the data generating device by the communicatingunit 31.

In the following explanation, the arbitrary bit string in the datagenerated by the data generating device is expressed as “a symbol”.

The data compressing unit 32 performs a compressing process for the datarecorded in the received data recording unit 34. This compressingprocess is realized with a data analyzing process and a data convertingprocess. The data analyzing process is a process of analyzing astatistical special feature of the data that is a target of thecompression. The information containing the result analyzed in this dataanalyzing process is referred to as a data analysis result. As anexample of an analysis of the statistical special feature, derivation ofthe appearance frequency (the number of times of the appearances) ofeach symbol within the data that is a target of compression can belisted. Hereinafter, for convenience, derivation of the appearancefrequency of each symbol is referred to as preparation of a frequencytable in some cases. Further, the information indicative of theappearance frequency of each symbol is referred to as a frequency tablein some cases.

Herein, the statistical special feature, being a target of analysis inthe data analyzing process of the compressing process, will beexplained. This statistical special feature is a statistical specialfeature having the characteristic that “the analysis result of thestatistical special feature of the third aggregation that is comprisedof all of the elements of the first aggregation and the elements of thesecond aggregation can be computed from the analysis result derived as astatistical special feature of the first aggregation (the first analysisresult), and the analysis result derived as a statistical specialfeature of the second aggregation (the second analysis result) withoutthe elements of the third aggregation listed”. That is, the statisticalspecial feature has the characteristic that the analysis result of thestatistical special feature of the third aggregation can be derived fromthe first analysis result and the second analysis result even though theindividual elements of the third aggregation are not specified when thefirst analysis result and the second analysis result have been derived.Herein, the element of the first aggregation and the element of thesecond aggregation are symbols. Also with the above-mentioned appearancefrequency of the symbol, the analysis result of the third aggregation(the appearance frequency of each symbol) can be derived even thougheach of the elements of the first and second aggregations is notrecognized at all when the appearance frequency of each symbol in thefirst aggregation and the appearance frequency of each symbol in thesecond aggregation are obtained. That is, a sum of the number of timesof the appearances of each symbol in the first aggregation and thenumber of times of the appearances of each symbol in the secondaggregation is computed for each symbol. Thus, the appearance frequency(frequency table) is equivalent to the statistical special featurehaving the foregoing characteristic. As another example of such astatistical special feature, a combination of an average value and thenumber of the elements, a combination of the maximum value and theminimum value of the element, or the like can be listed.

Owing to the characteristic of the statistical special feature asmentioned above, in the data analyzing process, the data analysis resultof the data (the elements of the third aggregation) in which anarbitrary pieces of the data (the elements of the first aggregation andthe second aggregation) have been coupled can be generated from the dataanalysis results (the data analysis results of the first aggregation andthe second aggregation) that are obtained by performing the dataanalyzing process for individual pieces of the data. Additionally, insuch a manner, the process of deriving the analysis result of the thirdaggregation from the data analysis results of the first aggregation andthe second aggregation is performed by the data relaying device.

The data converting process is a process of converting the data, being atarget of compression, into the compressed data of which the size issmall by employing the data analysis result. For example, it is assumedthat the data compressing unit 32 performs the process of deriving theappearance frequency of each symbol being contained in the data receivedfrom the data generating device as a data analyzing process. The datacompressing unit 32 performs, for example, the process of replacing eachsymbol with a Huffman code of each symbol being derived based upon theappearance frequency as a data converting process subsequent to theabove data analyzing process.

In the following explanation, a unit of the bit string (i.e. the bitstring after the data converting process) obtained in the dataconverting process of the compressing process is referred to as “acode”. In the above-mentioned example, the Huffman code corresponding toeach symbol is equivalent to “a code”. Further, information in whicheach symbol before the data converting process and each code replacingthe above symbol have been caused to correspond one versus one isreferred to as “data conversion information”. As an example of the dataconversion information, a code table in which the symbol and the codehave been caused to correspond to each other, or the like can be listed.

Further, in the following explanation, the bit string in which the dataconversion information and the data analysis result have been added tothe code generated in the compressing process is referred to as alreadycompressed data.

The data compressing unit 32 generates the already compressed data byadding the data conversion information and the data analysis result tothe code generated in the compressing process, and transmits the abovealready compressed data to the data relaying device by employing thecommunicating unit 31. The transfer destination information governswhich data relaying device, out of the data relaying devices that rankhigher by one hierarchy, the already compressed data is transmitted to.

The symbol dictionary recording unit 33 records the dictionary data fordefining the symbol, being a target of analysis in the data analyzingprocess of the compressing process, and the symbol, being a target ofconversion in the data converting process of the compressing process.For example, when the frequency table is prepared as a data analyzingprocess, and a conversion to the Huffman code is made as a dataconverting process, the symbol dictionary recording unit 33 recordsinformation (dictionary data) for deciding the symbol for which thefrequency table is prepared, or a conversion to the Huffman code ismade, out of the symbols being contained in the data received from thedata generating device. Additionally, when the frequency table isprepared as a data analyzing process, and a conversion to the Huffmancode is made as a data converting process like the case of theabove-mentioned example, the symbol, being a target of analysis in thedata analyzing process, and the symbol, being a target of conversion inthe data converting process, are identical to each other.

The symbol dictionary recording unit 33 and the received data recordingunit 34 are realized with the storing device. The data compressing unit32 may be realized, for example, with CPU that operates according to aprogram. This CPU may execute an operation of causing the received datarecording unit 34 to store the data received by the communicating unit31. Further, the data compressing unit 32 (CPU) may load the programstored in the storing device that the data compressing device includesto perform the compressing process (the data analyzing process and thedata converting process) according to the above program. Further,whenever performing the data analyzing process, the data compressingunit 32 may copy a program for executing the data analyzing process toits own storing device from the outside of the data compressing deviceso as to perform the data analyzing process according to the aboveprogram.

Further, as an example of the data analyzing process of the statisticalspecial feature, the preparation of the frequency table, the derivationof the number of the elements and the average value, the derivation ofthe maximum value and the minimum value, or the like can be listed;however, the data compressing unit 32 does not need to perform all ofthe various data analyzing processes, but performs the data analyzing ofone kind. For example, the data compressing unit 32 may be configured toprepare the frequency table and not to perform the derivation of thenumber of the elements and the average value and the derivation of themaximum value and the minimum value. When the data compressing unit 32is configured to perform plural kinds of the data analyzing processes,it may load a program responding to the kind of the data analyzingprocess so as to perform the data analyzing process according to theabove program.

The data compressing unit 32, when preparing the frequency table, countsthe number of the symbols being contained in the data received from thedata generating device for each symbol decided in the dictionary datastored in the symbol dictionary recording unit 33, and defines anaggregation of sets of the symbol and the counting result of the symbolto be a data analysis result.

Further, when a combination of the average value and the number of theelements is employed as a statistical special feature, the datacompressing unit 32 numerically expresses the element of the data so asto obtain the average value, and counts the number of the elements.Further, when the maximum value and the minimum value are employed as astatistical special feature, the data compressing unit 32 searches forthe maximum value and the minimum value that are obtained at the case ofnumerically expressing the element of the data so as to obtain themaximum value and the minimum value. As a technique of numericallyexpressing the element being contained in the data, there exists thetechnique of alternatively reading the bit string signifying eachelement by means of the binary digit; however the element may benumerically expressed with the other techniques. The statistical specialfeature and the data analyzing process thereof listed herein are onlyexemplification, and the data analyzing process may be performed byemploying the other statistical special features.

FIG. 3 is a block diagram illustrating a configuration example of thedata relaying device. Each of the data relaying devices (the datarelaying device 1,1 to the data relaying device 3,5 in an example shownin FIG. 1) includes a communicating unit 41, a received data recordingunit 42, a transfer destination information recording unit 45, a symbolclassifying unit 43, a data recompressing unit 44, a transferdestination deciding unit 46, and a symbol aggregation clusteringinformation acquiring unit 47. While FIG. 3 shows the data relayingdevice 3,1, out of the respective data relaying devices shown in FIG. 1,each of the data relaying devices except the devices for transmittingthe data to its own device (the data compressing devices 1 to N1 shownin FIG. 3), and the devices (the data relaying devices 2,1 to the datarelaying device 2,3 shown in FIG. 3), being a data transfer destination,is identical to the other in the configuration. For example, the datarelaying devices of the first hierarchy, which receive the data from thedata relaying devices of the second hierarchy, and transfer the data tothe data collecting device 7, are configured similarly to the datarelaying device shown in FIG. 3.

The communicating unit 41 is a device for transmitting/receiving thedata such as Ethernet (Registration Trademark). The communicating unit41 receives the data from a plurality of the data compressing devices orthe data relaying devices. The received data recording unit 42 is adevice for recording the data in which the receiving time has beenadditionally affixed to the data received by the communicating unit 41(each piece of the data received from a plurality of the datacompressing devices or the data relaying device). The process ofadditionally affixing the receiving time to the data received by thecommunicating unit 41, and causing the received data recording unit 42to store it is performed, for example, by the CPU for realizing eachunit of the data relaying device.

The data recompressing unit 44 recompresses the already compressed data.The data recompressing unit 44 realizes the recompression of the data byreplacing the code being contained in the received already compresseddata with other codes. At this time, while the compressed code isconverted into the symbol by the symbol classifying unit 43, it is notthat the data recompressing unit 44 compresses this symbol. That is, itis not that the data recompressing unit 44 expands the compressed data,and recompresses the expanded data. While the process of returning thecode to the symbol is performed, the data recompressing unit 44 realizesthe recompression by converting the code itself into another code. Thus,the load required for the recompressing process can be reduced, andfurther, the process time of the recompression can be made short. Aconfiguration of the data recompressing unit 44 will be described later.

The transfer destination information recording unit 45 records thetransfer destination information in which a range of the aggregation ofthe symbols defined for each the upper-place data relaying device, beinga transfer destination, and the destination information of each datarelaying device being contained in the upper-place data relaying devicegroup have been caused to correspond to each other. The so-called rangeof the aggregation of the symbols is a range of the symbols decided foreach data relaying device that ranks higher by one hierarchy. Forexample, when the data relaying devices that rank higher by onehierarchy are the data relaying device 2,1 to the data relaying device2,3 and that symbols “0000”, “1111”, and “00001111” are destined to betransmitted to the data relaying device 2,1 (more specifically, the dataobtained by compressing these symbols is destined to be transmitted),these three symbols become a range of the aggregation of the symbols.Likewise, when a symbol “0110” is destined to be transmitted to the datarelaying device 2,2 (more specifically, the data obtained by compressingthis symbol is destined to be transmitted), the symbol “0110” becomes arange of the symbol aggregation. The transfer destination information isdecided for each hierarchy of the data relaying device, and the transferdestination information recording units 45 of the data relaying devicebelonging to the identical hierarchy stores the common transferdestination information. Hereinafter, the range of the aggregation ofthe symbols decided for each upper-place data relaying device, being adata transfer destination, is referred to as a symbol aggregation.

The transfer destination information is generated by the transferdestination information updating device 5 to be later described (notshown in FIG. 1. See FIG. 7), and is recorded by the transferdestination information recording unit 45 via the communicating unit 41.

The symbol classifying unit 43 converts the code into the symbol byemploying the data conversion information within the already compresseddata recorded in the received data recording unit 42. The symbolclassifying unit 43 classifies each symbol obtained by the conversionaccording to the symbol aggregation decided for each data relayingdevice, being a transfer destination, by employing the transferdestination information recorded in the transfer destination informationrecording unit 45, and transmits it to the data recompressing unit 44.For example, the symbol classifying unit 43 previously divides a storageregion of the storing device (an already-compressed data recording unit441 that the data recompressing unit 44 includes. See FIG. 5) that thedata relaying device includes for each symbol aggregation decided foreach data relaying device, and causes the region of the symbolaggregation to which the symbol belongs to store each symbol obtained bythe conversion and the already compressed data. The symbol classifyingunit 43 classifies the code as well corresponding to each symbolobtained by the conversion, being a code contained in the alreadycompressed data, in line with the symbol, and transmits it to the datarecompressing unit 44. Further, it also classifies the data conversioninformation and the data analysis result contained in the alreadycompressed data in line with the symbol, and transmits it to the datarecompressing unit 44.

Further, the symbol classifying unit 43 prepares a frequency table ofthe symbol obtained by converting the compressed code into the symbol.That is, it counts the number of times of the appearances of the symbolfor each symbol obtained by converting the code, and generatesinformation (a frequency table) in which the symbol and the number oftimes of the appearances of the symbol has been caused to correspond toeach other. The symbol classifying unit 43 causes an execution historyrecording unit 471 that the symbol aggregation clustering informationacquiring unit 47 includes to store the above frequency table. Herein,when the frequency table has been prepared in the data analyzing processthat is performed at the time that the data compressing device compressthe data, and has been already contained in the already compressed data,the symbol classifying unit 43 does not need to prepare the frequencytable, and to cause the execution history recording unit 471 to storeit. When the frequency table has been contained in the alreadycompressed data as a data analysis result, the transfer destinationdeciding unit 46 causes the execution history recording unit 471 tostore the frequency table contained in the already compressed data,which has been caused to be contained in the execution historyinformation. The execution history recording unit 471 will be describedlater by making a reference to FIG. 4. The execution history informationwill be also described later.

The transfer destination deciding unit 46 decides the data relayingdevice, being a transmission destination of the already compressed datagenerated by the data recompressing unit 44, by employing the transferdestination information stored in the transfer destination informationrecording unit 45. And, the transfer destination deciding unit 46transmits the already compressed data to the decided data relayingdevice by employing the communicating unit 41.

FIG. 4 is a block diagram illustrating the symbol aggregation clusteringinformation acquiring unit 47. The symbol aggregation clusteringinformation acquiring unit 47 includes the execution history recordingunit 471, a distance parameter computing unit 472, and a compressioninformation acquiring unit 473.

The execution history information is recorded in the execution historyrecording unit 471. The execution history information contains thecommunication speed of the already compressed data transferred by thetransfer destination deciding unit 46, the time required for therecompressing process by the data recompressing unit 44, the size of thealready compressed data generated in the recompressing process, the dataanalysis result being contained in the already compressed data, the datarelaying device identification information allotted for each datarelaying device, and the hierarchy number. A specific example of theexecution history information will be described later by making areference to FIG. 37. The recording of the execution history informationinto the execution history recording unit 471 is carried out by thetransfer destination deciding unit 46. The hierarchy number and the datarelaying device identification information being contained in theexecution history information stored by the execution history recordingunit 471 is the hierarch number and the identification information ofthe data relaying device itself storing the above execution historyinformation.

The distance parameter computing unit 472 loads the communication speedof the already compressed data transferred by the transfer destinationdeciding unit 46, out of the execution history information recorded inthe execution history recording unit 471. Further, the distanceparameter computing unit 472 makes a reference to the execution historyinformation recorded in the execution history recording unit 471, andcomputes the processing speed in the recompressing process by dividingthe size of the already compressed data by the time required for therecompressing process. Next, the distance parameter computing unit 472transmits the loaded communication speed, the computed processing speed,the data relaying device identification information being contained inthe execution history information, and the hierarchy number to thetransfer destination information updating device 5.

The compression information acquiring unit 473 loads the frequency tableof the symbol recorded in the execution history recording unit 471, andtransmits the above frequency table to the transfer destinationinformation updating device 5. Additionally, when the frequency tablehas been contained in the already compressed data as a data analysisresult, and the above frequency table has been recorded as one part ofthe execution history information, the compression information acquiringunit 473 loads the frequency table recorded as one part of the executionhistory information. When the data analysis result contained in thealready compressed data is not a frequency table, the symbol classifyingunit 43 generates the frequency table, and causes the execution historyrecording unit 471 to store it, whereby the compression informationacquiring unit 473 loads the above frequency table and transmits it tothe transfer destination information updating device 5.

Additionally, each of the distance parameter computing unit 472 and thecompression information acquiring unit 473 transmits the information tothe transfer destination information updating device 5 via thecommunicating unit 41.

FIG. 5 is a block diagram illustrating the data recompressing unit 44.The data recompressing unit 44 includes an already compressed datarecording unit 441, a data analysis result acquiring unit 442, a dataanalysis result synthesizing unit 443, a data conversion informationacquiring unit 444, a data conversion information preparing unit 445,and a data converting unit 446.

The already compressed data recording unit 441 is a storing device forrecording the already compressed data that is sent from the symbolclassifying unit 43, being the already compressed data transmitted fromthe other plural data relaying devices. The already compressed data isclassified for each symbol aggregation by the symbol classifying unit43, and stored in the already compressed data recording unit 441.

The data analysis result acquiring unit 442 acquires the data analysisresult from the already compressed data stored in the already compresseddata recording unit 441 for each symbol aggregation.

The data analysis result synthesizing unit 443 generates theby-symbol-aggregation data analysis result of the entirety of thealready compressed data by employing the by-symbol-aggregation dataanalysis result acquired by the data analysis result acquiring unit 442.As explained already, the statistical special feature, being a target ofanalysis in the data analyzing process of the compressing process, hasthe characteristic that “the analysis result of the statistical specialfeature of the third aggregation that is comprised of all of theelements of the first aggregation and the elements of the secondaggregation can be computed from the analysis result derived as astatistical special feature of the first aggregation (the first analysisresult), and the analysis result derived as a statistical specialfeature of the second aggregation (the second analysis result) withoutthe elements of the third aggregation listed”. Thus, the data analysisresult synthesizing unit 443 can generate the by-symbol-aggregation dataanalysis result of the entirety of the already compressed data from theby-symbol-aggregation data analysis result.

The data conversion information acquiring unit 444 acquires the dataconversion information symbol aggregation by symbol aggregation from thealready compressed data stored in the already compressed data recordingunit 441.

The data conversion information preparing unit 445 prepares the dataconversion information symbol aggregation by symbol aggregation byemploying the by-symbol-aggregation data analysis result of the entiretyof the already compressed data recomputed by the data analysis resultsynthesizing unit 443.

For example, it is assumed that plural kinds of the data analysisresults have been stored in the already compressed data recording unit441 as a result of having received the already compressed data from thea plurality of the relaying devices. Further, it is assumed that theabove data analysis result is a frequency table. The data analysisresult synthesizing unit 443 prepares the data analysis result(frequency table) of the entirety of the already compressed data storageaggregation by storage aggregation from each data analysis result(frequency table). The data conversion information preparing unit 445prepares the data conversion information symbol aggregation by symbolaggregation from this entire data analysis result. For example, when thedata analysis result is a frequency table, the data conversioninformation preparing unit 445 derives the Huffman codes of individualsymbols based upon the entire data analysis result (frequency table),and defines the information in which the above Huffman code and thesymbol have been caused to correspond to each other to be new dataconversion information.

The data converting unit 446 converts the codes of the alreadycompressed data received from the already compressed data recording unit441 into the codes within the data conversion information generated bythe data conversion information preparing unit 445 from the dataconversion information acquired by the data conversion informationacquiring unit 444, and the data conversion information generated by thedata conversion information preparing unit 445, and transmits it to thetransfer destination deciding unit 46. The data conversion informationacquired by the data conversion information acquiring unit 444 is dataconversion information contained in the already compressed data receivedby the data relaying device. For example, it is assumed that the symbol“0000” and a code “0110” have been caused to correspond to each other inthis data conversion information. Further, it is assumed that the symbol“0000” and a code “00” have been caused to correspond to each other inthe data conversion information generated by the data conversioninformation preparing unit 445. In this case, the data converting unit446 converts the code “0110” within the already compressed datacorresponding to the symbol “0000” into “00” according to dataconversion information generated by the data conversion informationpreparing unit 445 so as to recompress the data. The data conversioninformation acquired by the data conversion information acquiring unit444 is referred to as old data conversion information, and the dataconversion information generated by the data conversion informationpreparing unit 445 is referred to as new data conversion information.Like the case of the above-mentioned example, the original symbol hasbeen uniquely decided from the code within the already compressed dataowing to the old data conversion information. Further, the new codecorresponding to the symbol has been decided in the new data conversioninformation. The data converting unit 446 retrieves the symbol caused tocorrespond to the code within the already compressed data from the olddata conversion information, further, retrieves the code caused tocorrespond to the above symbol from the new data conversion information,and replaces the code within the already compressed data with the abovecode. In such a manner, it is not that the data converting unit 446performs the recompressing process for the symbol recovered from thecode, but that it replaces the code within the already compressed datawith the another code so as to recompress the data. And, the dataconverting unit 446 generates the already compressed informationcontaining the after-recompression code, the new data conversioninformation, and the new data analysis result prepared by the dataanalysis result synthesizing unit 443.

The symbol classifying unit 43, the transfer destination deciding unit46, the distance parameter computing unit 472, the compressioninformation acquiring unit 473, the data analysis result acquiring unit442, the data analysis result synthesizing unit 443, the data conversioninformation acquiring unit 444, the data conversion informationpreparing unit 445, and the data converting unit 446 of the datarelaying device are realized, for example, with the CPU that operatesaccording to the program.

FIG. 6 is a block diagram illustrating a configuration example of thedata collecting device 7. The data collecting device 7 includes acommunicating unit 11, a received data recording unit 12, a dataanalysis result acquiring unit 13, a basic symbol description formatrecording unit 15, a derivative symbol description format recording unit17, a code operating unit 14, a code operation developing unit 16, andan operation result recording unit 18.

The communicating unit 11, similarly to the communicating unit 14 thateach data relaying device includes, is a device for receiving the datafrom the data relaying device. The received data recording unit 12 is astoring device similar to the received data recording unit 42 that eachdata relaying device includes.

The data analysis result acquiring unit 13 acquires the data analysisresult symbol aggregation by symbol aggregation from the alreadycompressed data stored in the received data recording unit 12. Further,it acquires the data conversion information symbol aggregation by symbolaggregation from the already compressed data stored in the received datarecording unit 12. That is, the data analysis result acquiring unit 13acquires information similar to the information that the data analysisresult acquiring unit 442 and the data conversion information acquiringunit 444, which each data relaying device includes, acquire.

The basic symbol description format recording unit 15 is a storingdevice for recording symbol description information of the symbolrecorded in the dictionary data recorded in the symbol dictionaryrecording unit 33 of the each of the data compressing devices 1 to N5,being a description format. In the basic symbol description formatrecording unit 15, the basic symbol, out of the symbols decided in thedictionary data of the symbol dictionary recording unit 33 of each ofthe data compressing device 1 to N5, and the format description of theabove basic symbol have been pre-stored correspondingly to each other.The basic symbol is a symbol that cannot be divided beyond it (forexample, the symbol expressing one character). The description formatbeing contained in the symbol description information is a symbol inwhich the basic symbol has been described in another expression. Forexample, when the character code differs, the bit string expressing thecommon character also differs. Upon taking a specific example, thecharacter of shift JIS and the character of another character codediffer from each other in the bit string even though these charactersare identical. The description format being contained in the symboldescription information is a symbol in which the basic symbol isexpressed with a different bit string in such a manner. Such symboldescription information makes it possible to unify the identicalcharacter expressed with a different bit string into a character havinga bit string in line with one specification (character code).Additionally, the symbol description information has been pre-decided.

Further, the symbol that is obtained by combining the basic symbols isreferred to as a derivative symbol. For example, the symbol signifyingthe character string having two characters or more that is obtained bycombining the basic symbols is equivalent to the derivative symbol.Further, the so-called description format of the derivative symbol is anaggregation of individual basic symbols constituting the derivativesymbol. The derivative symbol description format recording unit 17 is astoring device for storing derivative symbol configuration informationin which the derivative symbol that is configured of a plurality of thebasic symbols, and a set of a plurality of the basic symbolsconstituting the above derivative symbol (the description format of thederivative symbol) have been caused to correspond to each other.

The basic symbol being contained the symbol description information andthe description format of the basic symbol differs from each other, forexample, in the specification such as the character code. On the otherhand, the specification of the derivative symbol being contained in thederivative symbol configuration information and that of the descriptionformat of the derivative symbol are common because the derivative symbolis a basic symbol obtained in which the basic symbols have beencombined, and the description format of the derivative symbol is anaggregation of the basic symbols constituting the derivative symbol inthe derivative symbol configuration information.

The code operating unit 14 derives a statistical value of the basicsymbols converted into the codes within the already compressed data (forexample, the frequency table of the basic symbol), and a statisticalvalue of the derivative symbols (for example, the frequency table of thederivative symbol) by employing the data analysis result acquired by thedata analysis result acquiring unit 13, and the symbol descriptioninformation acquired from the basic symbol description format recordingunit 15.

The code operation developing unit 16 computes the statistical value ofthe basic symbols constituting the derivative symbol from a combinationof the basic symbols constituting the derivative symbol acquired fromthe derivative symbol description format recording unit 17, and thestatistical value of the derivative symbols computed by the codeoperating unit 14. The code operation developing unit 16 newly computesthe statistical value of the basic symbols by coupling the abovestatistical value of the basic symbols, and the statistical value of thebasic symbols computed by the code operating unit 14. The operationresult recording unit 18 is a storing device for storing the statisticalvalue of the basic symbols computed by the code operation developingunit 16.

The data analysis result acquiring unit 13, the code operating unit 14,and the code operation developing unit 16 are realized, for example,with the CPU that operates according to the program.

FIG. 7 is a block diagram illustrating a configuration example of thetransfer destination information updating device 5. The transferdestination information updating device 5 includes a communicating unit51, a symbol distribution generating unit 53, a distance parameteracquiring unit 52, a symbol aggregation clustering unit 54, a datarelaying device information recording unit 56, and a transferdestination information generating unit 55.

The communicating unit 51 is a device similar to the communicating unit41 that each data relaying device includes. The communicating unit 51receives the frequency table of the symbol, the processing speed in therecompressing process and the communication speed being contained in theexecution history information, the data relaying device identificationinformation, and the hierarchy number from symbol aggregation clusteringinformation acquiring unit 47 of each data relaying device. Further, thecommunicating unit 51 transmits the transfer destination information toeach data relaying device.

The symbol distribution generating unit 53 acquires the frequency tablefrom the compression information acquiring unit 473 within each datarelaying device via the communicating unit 51. And, the symboldistribution generating unit 53 prepares a frequency table of the symbolwithin the data received from the other data relaying devices or thedata compressing device for a constant time by all data relaying devicesby employing the frequency table acquired from the compressioninformation acquiring unit 473 within each data relaying device.

The distance parameter acquiring unit 52 acquires the processing speedof the recompressing process in each data relaying device, thecommunication speed contained in the execution history information, thedata relaying device identification information, and the hierarchynumber from the distance parameter computing unit 472 within each datarelaying device via the communicating unit 51.

The symbol aggregation clustering unit 54 classifies the symbols withinthe data received for a constant time by the data relaying device foreach hierarchy of the data relaying device by employing thecommunication speed and the processing speed (the processing speed ofthe recompressing process in each data relaying device) received fromthe distance parameter acquiring unit 52, and the frequency table of thesymbol within the data received for a constant time by all data relayingdevices, which has been prepared by the symbol distribution generatingunit 53. And, the symbol aggregation clustering unit 54 allots theidentification information of the data relaying devices of theupper-place hierarchy to the classified group hierarchy by hierarchy. Inaddition, the symbol aggregation clustering unit 54 generates theinformation hierarchy by hierarchy in which the aggregation of thesymbols (equivalent to the symbol aggregation already explained)belonging to each group, and the identification information of the datarelaying devices of the upper-place hierarchy allotted to each grouphave been caused to correspond to each other. The information in whichthis symbol aggregation and the identification information of the datarelaying devices of the upper-place hierarchy have been caused tocorrespond to each other is referred to as symbol cluster information.When the symbol aggregation clustering unit 54 classifies the symbolswithin the data and generates the symbol cluster information, itgenerates the symbol cluster information so that the following twoconditions are satisfied.

A first condition is that a deviation of the frequency table of thesymbol within the group becomes larger than that of the frequency tableof the symbol generated by the symbol distribution generating unit 53. Asecond condition is that a magnitude relation, which is obtained at thetime of comparing the total number of the frequencies of respectivesymbols belonging to the group (the total number of times of theappearances of respective symbols belonging to the group) group bygroup, coincides with a magnitude relation of a sum of the communicationspeed and the processing speed of the data relaying device (the datarelaying device of the upper-place hierarchy) allotted to each group.For example, it is assumed that when the symbols are classified intogroup A, group B, and group C, the total number of times of theappearances of each symbol belonging to each group is a, b, and c,respectively, and a<b<c. It is assumed that the data relaying devices ofthe upper-place hierarchy that are allotted to the groups A, B, and Care P, Q, and R, respectively, and the sum of the communication speedand the processing speed of each of the data relaying devices P, Q, andR is p, q, and r, respectively. At this time, if a<b<c, the datarelaying devices of the upper-place hierarchy are allotted to each groupso that p<q<r holds. Further, the so-called deviation of the frequencytable in the first condition is a ratio of the appearance frequency ofthe symbol of which the appearance frequency (the number of times of theappearances) is largest to all frequencies (the number of times of theappearances of all symbols) within the frequency table.

The data relaying device information recording unit 56 is a storingdevice for storing data relaying device information. The so-called datarelaying device information is information in which the identificationinformation of the data relaying device, the destination information ofthe data relaying device (for example, an IP address, a port number,etc.), and the hierarchy number of the data relaying device have beencaused to correspond to each other for each data relaying device.

The transfer destination information generating unit 55 loads the datarelaying device information from the data relaying device informationrecording unit 56. Further, the transfer destination informationgenerating unit 55 acquires the symbol cluster information from thesymbol aggregation clustering unit 54. And, the transfer destinationinformation generating unit 55 generates the transfer destinationinformation in which the destination information of the upper-place datarelaying device, out of the data relaying devices of each hierarchy, andthe aggregation of the symbols being transmitted to the upper-place datarelaying device have been caused to correspond to each other from thedata relaying device information and the symbol cluster information. Thetransfer destination information generating unit 55 transmits thetransfer destination information generated hierarchy by hierarchy to thedata relaying devices of each hierarchy via the communicating unit 51.At this time, it transmits to each data relaying device the transferdestination information responding to the hierarchy to which the abovedata relaying device belongs. Additionally, the data relaying device,upon receipt of the transfer destination information, causes thetransfer destination recording unit 45 to store the above transferdestination information.

The distance parameter acquiring unit 52, the symbol distributiongenerating unit 53, the symbol aggregation clustering unit 54, and thetransfer destination information generating unit 55 are realized, forexample, with the CPU that operates according to the program.

Next, an operation will be explained.

FIG. 8 is a flowchart illustrating an example of an operation of thedata collection system of the present invention. An operation ofcollecting the data by the data collection system including each datagenerating device, each compressing device, each data relaying device,and the data collecting device 7 will be explained by making a referenceto FIG. 1 and FIG. 8.

FIG. 8 exemplifies an operation of the case that the data generatingdevices 1′ to N1′, and the data generating devices N1+1′ to N2 generatethe data, and the data relaying device 3,1, the data relaying device3,2, the data relaying device 2,1, the data relaying device 2,2, and thedata relaying device 1,1 transfer the data; however an operation ofother data generating devices and the other data relaying devices isalso similar.

Each of the data generating device 1′ to the data generating device N1′,and the data generating device N1+1′ to the data generating device N2′includes, for example, an RFID reader, and generates the data such as atag ID by reading off a tag ID etc. from an RFID tag. In the followingexplanation, the case that each data generating device includes the RFIDreader for reading off the data from the RFID tag so as to generate thedata is exemplified. The data generating device 1′ to the datagenerating device N1′ transmit the generated data to corresponding datacompressing devices 1 to N1, respectively, and the data generatingdevice N1+1′ to the data generating device N2′ as well similarlytransmit the generated data to corresponding data compressing devicesN1+1 to N2, respectively (steps S101 and S102).

Next, the data compressing device 1 to N1 compress the data received inS101, and transmit the already compressed data (the data in which thedata conversion information and the data analysis result have been addedto the code obtained by the compression) to the data relaying device 3,1(step S103). Likewise, the data compressing device N+1 to N2 compressthe data received in S102, and transmit the already compressed data tothe data relaying device 3,2 (step S104).

Next, the data relaying device 3,1 recompresses the already compresseddata received in the step S103 from the data compressing devices 1 toN1, and transmits the already compressed data to the upper-place datarelaying device group (in this example, the data relaying device 2,1 andthe data relaying device 2,2)(step S200A). The data relaying device 3,2recompresses the already compressed data received in the step S104 fromthe data compressing devices N1+1 to N2, and transmits the alreadycompressed data to the upper-place data relaying device group (stepS200B). The data relaying device 2,1 and the data relaying device 2,2transmit the already compressed data received from the low-place datarelaying device group to the upper-place data relaying device group (inthis example, the data relaying device 1,1) (steps S200C and S200D).

Next, the data relaying device 1,1 recompresses the already compresseddata received from the data relaying device 2,1 and the data relayingdevice 2,2 each of which is a low-place data relaying device group, andtransmits the already compressed data to the data collecting device 7(step S200E).

The data collecting device 7 performs an operating process for thealready compressed data received from the data relaying device 1,1 (stepS300). For example, it obtains the number of times of the appearances ofeach symbol converted into the code being contained in the alreadycompressed data.

Next, an operation of the data compressing device will be explained bymaking a reference to FIG. 2 and FIG. 9. FIG. 9 is a flowchartillustrating an example of an operation of the data compressing device.Herein, the case that the data generating device 1′ generates the data,and the data compressing device 1 compresses the data will beexemplified for explanation; however an operation of the other datagenerating devices and the other data compressing devices is alsosimilar.

At first, the data generating device 1′ reads off the data such as thetag ID from the RFID tag with the RFID reader, generates the data suchas the tag ID, and transmits the above data to the data compressingdevice 1 (step S1010). Next, the communicating unit 31 that the datacompressing device 1 includes receives the data transmitted in S1010(Step S1011).

Next, the data compressing device 1 causes the received data recordingunit 34 that the data compressing device 1 includes to store the datareceived in S1011 by the communicating unit 31 (step S1012). Thisoperation is performed, for example, by the CPU that the datacompressing device includes. Further, this CPU may causes the receiveddata recording unit 34 to store the receiving time as well together withthe received data.

After the step S1012, the data compressing unit 32 loads the dictionarydata from the symbol dictionary recording unit 33 (step S1013). Next,the data compressing unit 32 compresses the data recorded in S1012 bythe received data recording unit 34 by employing the dictionary dataacquired in S1013 (step S1014). In this compressing process, the dataanalyzing process and the data converting process are performed. Thesymbol, being a target of analysis in the data analyzing process of thecompressing process, and the symbol, being a target of conversion in thedata converting process of the compressing process, have been decided bythe dictionary data loaded in the step S1013. As an example of the dataanalyzing process, for example, the process in which the datacompressing unit 32 counts the number of times of the appearances withinthe received data for each decided symbol, and derives the Huffman codeof each symbol based upon its result can be listed. In this case, thedata compressing unit 32 converts each symbol into the derived Huffmancode in the data converting process. The data analyzing process and thedata converting process shown herein are only exemplification, and thecompression may be carried out in other aspects.

Next, an operation of the data relaying device will be explained bymaking a reference to FIG. 3, FIG. 10, and FIG. 11. Each of FIG. 10 andFIG. 11 is a flowchart illustrating an example of an operation of thedata relaying device.

The data relaying device firstly receives the already compressed datafrom the low-place data relaying device group via the communicating unit41 (step S201). Additionally, the data relaying devices of thelowest-place hierarchy (in an example shown in FIG. 1, the data relayingdevice 3,1 to the data relaying device 3,5) receive the alreadycompressed data from the data compressing device via the communicatingunit 41.

After the step S201, the data relaying device causes the received datarecording unit 42 that the data relaying device includes to store thealready compressed data received in S201 by the communicating unit 41.This operation is performed, for example, by the CPU that the datarelaying device includes. Further, this CPU causes the received datarecording unit 42 to store, together with the received alreadycompressed data, the receiving time as well of the above alreadycompressed data.

Next, the symbol classifying unit 43 loads the transfer destinationinformation stored in the transfer destination information recordingunit 45 (step S203). After the S203, the symbol classifying unit 43converts the compressed codes into the symbols by employing the dataconversion information within the already compressed data, andclassifies respective symbols obtained by the conversion into the symbolaggregation that has been defined for each data relaying device, being atransfer destination, in the transfer destination information loaded inS203 (step S204).

Next, the symbol classifying unit 43 transmits the already compresseddata and the symbol classified in S204 to the data recompressing unit 44(step S205). At this time, the symbol classifying unit 43 classifies thecode, data conversion information, and data analysis result as wellcontained in the already compressed data in line with the symbol, andtransmits them to the data recompressing unit 44.

After receiving the already compressed data from the symbol classifyingunit 43 in S205, the data recompressing unit 44 performs therecompressing process for the already compressed data transmitted inS205 by the symbol classifying unit 43 for each symbol aggregation (stepS206).

After the already compressed data has been generated in therecompressing process of S206, the data recompressing unit 44 transmitsthe above already compressed data to the transfer destination decidingunit 46 (step S209). Next, the transfer destination deciding unit 46loads the transfer destination information from the transfer destinationinformation recording unit 45 (step S210), and decides the destinationto which the already compressed data acquired in S209 is transmitted(step S211). Next, the transfer destination deciding unit 46 transmitsthe already compressed data to the device, being a destination, byemploying the communicating unit 41 (step S212). Continuously, thetransfer destination deciding unit 46 causes the execution historyrecording unit 471 that the symbol aggregation clustering informationacquiring unit 47 includes to store the execution history informationcontaining the communication speed at the time of transmitting thealready compressed data or the like (step S213).

Next, an operation of the recompressing unit 44 that the data relayingdevice includes will be explained by making a reference to FIG. 5 andFIG. 12. FIG. 12 is a flowchart illustrating an example of an operationof the recompressing unit 44.

At first, the already compressed data recording unit 441 within the datarecompressing unit 44 records the already compressed data sent in S205from the symbol classifying unit 43 (step S2041).

The data analysis result acquiring unit 442 acquires the data analysisresult symbol aggregation by symbol aggregation from the alreadycompressed data recording unit 441 (step S2042).

Next, the data conversion information acquiring unit 444 acquires thedata conversion information symbol aggregation by symbol aggregationfrom the already compressed data recording unit 441 (step S2043).

The data analysis result synthesizing unit 443 prepares the dataanalysis result for the already compressed data within the symbolaggregation from the by-symbol-aggregation data analysis result acquiredin S2042 by the data analysis result acquiring unit 442 (step S2044). Atthis time, it may derive the total number of the codes.

Next, the data conversion information preparing unit 445 preparers newdata conversion information symbol aggregation by symbol aggregationfrom the data analysis result for the already compressed data with thesymbol aggregation prepared in S2044 by the data analysis resultsynthesizing unit 443 (step S2045). It may employ the total number ofthe codes when preparing the new data conversion information.

The data converting unit 446 acquires the by-symbol-aggregation dataconversion information (old data conversion information) acquired inS2043 by the data conversion information acquiring unit 444, andfurther, acquires the by-symbol-aggregation data conversion information(new data conversion information) prepared in S2045 by the dataconversion information preparing unit 445 (step S2046). And, the dataconverting unit 446 replaces the codes listed in the old data conversioninformation with the codes listed in the new data conversion informationwith regard to the codes of the already compressed data recorded in thealready compressed data recording unit 441. And, the data convertingunit 446 generates the already compressed data containing the abovecode, the new data conversion information, and the new data analysisresult prepared in the step S2044. The data converting unit 446transmits the above already compressed data to the transfer destinationdeciding unit 46 (step S2047). Thereafter, the transfer destinationdeciding unit 46 performs the operation of the step S211 alreadyexplained.

Next, an operation of the data collecting device 7 will be explained bymaking a reference to FIG. 6, FIG. 13 and FIG. 14. Each of FIG. 13 andFIG. 14 is a flowchart illustrating an example of an operation of thedata collecting device 7.

At first, the communicating unit 11 receives the already compressed datafrom the data relaying devices of which the hierarchy number is smallest(i.e. the data relaying devices of the highest-place hierarchy) (stepS301), and causes the received data recording unit 12 to store thealready compressed data (step S302). The operation of causing thereceived data recording unit 12 to store the already compressed data isperformed, for example, by the CPU that the data collecting device 7includes. The data analysis result acquiring unit 13 acquires the dataanalysis result from the already compressed data recorded in the receivedata recording unit 12 (step S304).

The code operating unit 14 acquires the symbol description informationfrom the basic symbol description format recording unit 15, and acquiresthe description format of the derivative symbol expressed in acombination of the basic symbols recorded in the dictionary data fromthe derivative symbol format recording unit 17 (step S305).

Next, the code operating unit 14 derives the statistical value (forexample, the frequency table) of the symbols recorded in the dataconversion information contained in the already compressed data from thedata analysis result acquired in S304 by the data analysis resultacquiring unit 13. And the code operating unit 14 computes thestatistical value (for example, the frequency table) of the basicsymbols and the derivative symbols by making a reference to the symboldescription information acquired in S305 (step S306).

Next, the code operation developing unit 16 acquires a combination ofthe basic symbols constituting the derivative symbol from the derivativesymbol description format recording unit 17 (step S307), and computesthe statistical value of the basic symbols constituting the derivativesymbol from the statistical value of the derivative symbols computed inS306 by the code operating unit 14. The code operation developing unit16 couples the statistical value of the basic symbols and thestatistical value of the basic symbols computed in S306 by the codeoperating unit 14, and newly computes the statistical value of the basicsymbols (step S308).

Finally, the code operation developing unit 16 records the statisticalvalue of the basic symbols computed in S308 into the operation resultrecording unit 18 (step S309).

Next, an operation of the symbol aggregation clustering informationcollecting unit 47 that the data relaying device includes will beexplained by making a reference to FIG. 4, FIG. 15 and FIG. 16. Each ofFIG. 15 and FIG. 16 is a flowchart illustrating an example of anoperation of the symbol aggregation clustering information collectingunit 47.

The compression information acquiring unit 473 acquires the executionhistory information recorded in the execution history recording unit471, and acquires the data analysis result of the already compresseddata processed for a constant time by the transfer destination decidingunit 46 from the acquired execution history information (step S501).

Further, the compression information acquiring unit 473 acquires thefrequency table of the symbol (step S502). When the frequency table ofthe symbol has been derived as a data analysis result, the data analysisresult acquired in step S501 becomes a frequency table of the symbol.Further, when the information other than the frequency table of thesymbol has been derived as a data analysis result, the symbolclassifying unit 43 (see FIG. 3) generates the frequency table of thesymbol. In this case, the compression information acquiring unit 473acquires the frequency table of the symbol from the symbol classifyingunit 43 (step S502).

The compression information acquiring unit 473 transmits the frequencytable of the symbol to the transfer destination information updatingdevice 5 by employing the communicating unit 41 (step S503).

The distance parameter computing unit 472 acquires the communicationspeed (communication speed at the time of transmitting the alreadycompressed data) being contained in the execution history informationthat the transfer destination deciding unit 46 has caused the executionhistory recording unit 471 to store. Further, the distance parametercomputing unit 472 acquires the size of the already compressed datagenerated in the recompressing process, and the time required for therecompressing process from the above execution history information. And,the distance parameter computing unit 472 divides the size of thealready compressed data by the time required for the recompressingprocess, thereby to compute the processing speed of the recompressingprocess (step S601). The result of the division is a processing speed ofthe recompressing process.

Next, the distance parameter computing unit transmits the communicationspeed, the computed processing speed, and the data relaying deviceidentification information and the hierarchy number contained in theexecution history information to the transfer destination informationupdating device 5 (step S602).

The compression information acquiring unit 473 regularly performs theprocess of the steps S501 to S503, and the distance parameter computingunit 472 regularly performs the process of the steps S601 and S602.

Next, an operation of the transfer destination information updatingdevice 5 in this embodiment will be explained by making a reference toFIG. 7 and FIG. 17. FIG. 17 is an explanatory view illustrating anexample of an operation of the transfer destination information updatingdevice 5.

At first, the communicating unit 51 receives the frequency table of thesymbol within the already compressed data from the compressioninformation acquiring unit 473 that each data relaying device includes.Further, the communicating unit 51 receives the processing speed of thecompressing process or the recompressing process in each data relayingdevice, the communication speed of the process of transmitting thealready compressed data, the data relaying device identificationinformation, and the hierarchy number of the hierarch to which the datarelaying device belongs from the distance parameter computing unit 472that each data relaying device includes (step S401).

Next, the symbol distribution generating unit 53 acquires a plurality ofthe frequency tables of the symbols received in the step S401 by thecommunicating unit 51, and synthesizes them into one frequency table(step S402). The symbol distribution generating unit 53 performs theprocess of the step S402 hierarchy by hierarchy. That is, it synthesizesa plurality of the frequency tables into one frequency table hierarchyby hierarchy. In the step S402, it generates the frequency table of thesymbol within the data received for a constant time by all data relayingdevices. Further, the distance parameter acquiring unit 52 acquires thecommunication speed and the processing speed received in the step S401by the communicating unit 51 (step S403).

Next, the symbol aggregation clustering unit 54 generates the symbolcluster information (step S404). FIG. 18 is a flowchart illustrating anexample of an operation of generating the symbol cluster information.The symbol aggregation clustering unit 54 performs an operation shownbelow before commencing the process of step A1 shown in FIG. 18.

The symbol aggregation clustering unit 54 sorts a combination of thesymbol and the frequency of the above symbol in the descending order ofthe frequency in the frequency table (the frequency table generated inthe step S402) in which the symbol and the frequency (the number oftimes of the appearances) of the symbol have been caused to correspondto each other. The frequency table sorted in such a manner is called analready sorted frequency list. FIG. 19 is an explanatory viewillustrating an example of the already sorted frequency list. The symbolaggregation clustering unit 54 sorts a combination of the symbol and thefrequency of the above symbol in the descending order of the frequency,and affixes the rank to each element (herein, a combination of thesymbol and the frequency of the above symbol), thereby to generates thealready sorted frequency list.

Additionally, FIG. 19, and FIG. 20 to FIG. 23 shown below are anexemplification of each item of the information, respectively.

Further, the symbol aggregation clustering unit 54 extracts the datarelaying device identification information of the data relaying devicesto which the identical hierarchy number has been allotted from thereceived communication speed, processing speed, hierarchy number, anddata relaying device identification information, and generates theinformation in which the data relaying device identification informationhas been listed hierarchy by hierarchy. In addition, the symbolaggregation clustering unit 54 prepares the information in which thelisted data relaying device identification information, the total valueof the communication speed and the processing speed corresponding to thedata relaying device identification information, and the total number ofthe symbols each of which is a target of transfer have been caused tocorrespond to each other, and sorts a combination of the listed datarelaying device identification information, the total value of thecommunication speed and the processing speed, and the total number ofthe symbols each of which is a target of transfer in the descendingorder of the total value of the communication speed and the processingspeed. The symbol aggregation clustering unit 54 affixes theafter-sorting rank to each of these combinations. The informationprepared in such a manner is referred to as an already sorted datarelaying device list. The symbol aggregation clustering unit 54 extractsthe data relaying device identification information for each identicalhierarchy, and prepares the already sorted data relaying device listhierarchy by hierarchy. Thus, it follows that the symbol aggregationclustering unit 54 generates the already sorted data relaying devicelists of which the list number is equal to the number of the hierarchiesof the data relaying devices.

FIG. 20 is an explanatory view illustrating an example of the alreadysorted data relaying device list. FIG. 20 exemplifies the already sorteddata relaying device list of the hierarch number 2. Herein, the totalnumber of the symbols each of which is a target of transfer is a totalvalue of the frequencies of the symbols that are transferred to the datarelaying devices. When the symbol aggregation clustering unit 54generates the already sorted data relaying device list, it defines thetotal number of the symbols each of which is a target of transfer to be“0”. That is, the already sorted data relaying device list is generatedwith an initial value of the total number of the symbols each of whichis a target of transfer defined to be 0 (zero).

Next, the symbol aggregation clustering unit 54 derives the inflectionpoint list from the already sorted frequency list. The inflection pointlist is derived, for example, as described below. At first, the symbolaggregation clustering unit 54 generates a first-order differentialvalue list from the already sorted frequency list, and in addition,generates a second-order differential value list from the first-orderdifferential value list.

The symbol aggregation clustering unit 54 subtracts the frequency of thesymbol of which the rank is an n-th place from the frequency of symbolof which the rank is an (n+1)-th place in the already sorted frequencylist, and decides the rank of its subtraction result (referred to be asa first-order differential value) to be an n-th place. The symbolaggregation clustering unit 54 continues this process in the order ofn=1, 2, . . . until the process of the subtraction is completed. Theinformation obtained as a result is called a first-order differentialvalue list. FIG. 21 is an explanatory view illustrating an example ofthe first-order differential value list. In FIG. 21, for example, therank of “0”, being a result of having subtracted the frequency “400” ofthe first-place symbol from the frequency “400” of the second-placesymbol exemplified in FIG. 19, is defined to be a first place. The otherfirst-order differential values shown in FIG. 21 are also valuessimilarly derived.

In addition, the symbol aggregation clustering unit 54 subtracts thefirst-order differential value of which the rank is a n-th place fromthe first-order differential value of which the rank is an (n+1)-thplace in the first-order differential value list, and decides the rankof its subtraction result (referred to be as a second-order differentialvalue) to be an n-th place. The symbol aggregation clustering unit 54continues this process in the order of n=1, 2, . . . until the processof the subtraction is completed. The information obtained as a result iscalled a second-order differential value list. FIG. 22 is an explanatoryview illustrating an example of the second-order differential valuelist. In FIG. 22, for example, the rank of “−300”, being a result ofhaving subtracted the first-place first-order differential value “0”from the second-place first-order differential value “−300” exemplifiedin FIG. 21, is defined to be a first place. The other second-orderdifferential values shown in FIG. 22 are also values similarly derived.

In addition, when a mark of the second-order differential value has beenchanged from that of the second-order differential value that rankshigher by one in the second-order differential value list, the symbolaggregation clustering unit 54 extracts the rank of the second-orderdifferential value of which the mark has been changed. The symbolaggregation clustering unit 54 extracts the rank of the second-orderdifferential value of which the mark has been changed in the order ofthe rank of the second-order differential value list, and decides thenew rank for the extracted rank in the order of extraction. For example,in the second-order differential value list shown in FIG. 22, the markof “the second-place” second-order differential value is positive, and achange from the mark of the first-place second-order differential value(negative) has occurred. Thus, the symbol aggregation clustering unit 54extracts the above rank “second place” as an inflection point. Further,when a determination is made as to which rank is extracted as aninflection point in the order of the second-order differential valuelist, to begin with the first place, the above-mentioned “second place”is an inflection point that has been firstly extracted, so the rank ofthe above inflection point “second place” is newly decided to be a firstplace. The information of the inflection point and its rank acquired atthe time of having completed the extraction of the inflection point isreferred to as an inflection point list. FIG. 23 is an explanatory viewillustrating one example of the inflection point list derived asdescribed above.

Further, the symbol aggregation clustering unit 54 firstly generates thepart in which the hierarchy number and the data relaying deviceidentification information have been caused to correspond to each other,out of the symbol cluster information. While the symbol clusterinformation is generated by causing the hierarchy number, the symbolaggregation, the data relaying device identification information of thedata relaying device that ranks by one higher than the above hierarchynumber to correspond to each other, the symbol aggregation clusteringunit 54 firstly generates the part in which the hierarchy number and thedata relaying device identification information have been caused tocorrespond to each other with an initial value of the symbol aggregationdefined to be an empty aggregation.

Next, the symbol aggregation clustering unit 54 executes the process ofsteps A1 to A12 shown in FIG. 18. The process of the steps A1 to A12below is executed hierarchy by hierarchy by employing the already sortedfrequency list, the already sorted data relaying device list, and theinflection point lists each of which has been generated hierarchy byhierarchy.

The symbol aggregation clustering unit 54 acquires the first(first-place) element from the already sorted frequency list (step A1).The so-called element in the already sorted frequency list is acombination of “the rank”, “the symbol”, and “the frequency” for eachrank (see FIG. 19). In the step A1, the symbol aggregation clusteringunit 54 acquires a combination the rank, “being a first place”, and “thesymbol” and “the frequency” corresponding to the above rank. The element(a combination of “the rank, “the symbol”, and “the frequency”) that isacquired from the already sorted frequency list in the step A1 and thestep A12 to be later described is referred to as a process-targetfrequency element. For example, when the already sorted frequency listexemplified in FIG. 19 has been prepared, the symbol aggregationclustering unit 54 acquires a combination of the rank “first place”, thesymbol “1111” and the frequency “400” as a process-target frequencyelement in the step A1.

Continuously, the symbol aggregation clustering unit 54 acquires thefirst (first-place) element from the already sorted data relaying devicelist (step A2). The so-called element in the already sorted datarelaying device list is a combination of “the rank”, “the data relayingdevice”, “the total value of the communication speed and the processingspeed”, and “the total number of the transfer-target symbols” for eachrank (see FIG. 20). In the step A2, the symbol aggregation clusteringunit 54 acquires a combination of the rank, being “a first place”, “thedata relaying device” corresponding to the above rank, “the total valueof the communication speed and the processing speed” and “the totalnumber of the transfer-target symbols”. The element (a combination of“the rank”, “the data relaying device”, “the total value of thecommunication speed and the processing speed”, and “the total number ofthe transfer-target symbols”) that is acquired from the already sorteddata relaying device list in the step A2 and the step A5 to be laterdescribed is referred to as a process-target data relaying deviceelement. For example, when the already sorted data relaying device listexemplified in FIG. 20 has been prepared, the symbol aggregationclustering unit 54 acquires a combination of the rank “first place”, thedata relaying device identification information “2,1” the total value ofthe communication speed and the processing speed “210”, and the totalnumber of the transfer-target symbols “0” as a process-target datarelaying device element in the step A2.

After the step A2, the symbol aggregation clustering unit 54 determineswhether or not the rank in the already sorted frequency list of theprocess-target frequency element coincides with the element (inflectionpoint) within the inflection point list (step A3). For example, when acombination of the rank “first place”, the symbol “1111” and thefrequency “400” has been acquired as a process-target frequency element,and the inflection point list exemplified in FIG. 23 has been prepared,the symbol aggregation clustering unit 54 determines whether or not therank (first place) of the process-target frequency element coincideswith the inflection point (“2” in an example of FIG. 23) within theinflection point list. In this example, it is determined that they donot coincide with each other.

When the rank in the already sorted frequency list of the process-targetfrequency elements coincides with the element (inflection point) withinthe inflection point list in the step A3 (yes of the step A3), thesymbol aggregation clustering unit 54 deletes the element (inflectionpoint) with which the rank of the process-target frequency elementcoincides from the inflection point list (step A4). Continuously to thestep A4, the symbol aggregation clustering unit 54 acquires the elementof the rank obtained by adding 1 (one) to the rank of the process-targetdata relaying device element recently acquired (the rank lower by onethan that of recently acquired process-target data relaying deviceelement) as a process-target data relaying device element from thealready sorted data relaying device list (step A5). The process-targetdata relaying device element being acquired in the step A5 is also acombination of “the rank”, “the data relaying device”, “the total valueof the communication speed and the processing speed”, and “the totalnumber of the transfer-target symbols”. After the step A5, the symbolaggregation clustering unit 54 proceeds to the step A3, and repeats theprocess of the step A3 and the steps subsequent hereto.

When the rank in the already sorted frequency list of the process-targetfrequency elements does not coincide with the element (inflection point)within the inflection point list in the step A3 (no of the step A3), thesymbol aggregation clustering unit 54 compares the number of theelements of the already sorted frequency list with the number of theelements of the already sorted data relaying device list, and determineswhether or not the number of the elements of the already sortedfrequency list is larger than the number of the elements of the alreadysorted data relaying device list (step A6). For example, it is assumedthat the already sorted frequency list exemplified in FIG. 19 and thealready sorted data relaying device list exemplified in FIG. 20 havebeen prepared. In this case, the number of the elements of the alreadysorted frequency list exemplified in FIG. 19 is “5”, and the number ofthe elements of the already sorted data relaying device list exemplifiedin FIG. 20 is “3”. The symbol aggregation clustering unit 54 comparesthese two elements, and determines whether or not the number of theelements of the already sorted frequency list is larger than the numberof the elements of the already sorted data relaying device list. In thecase of the foregoing exemplification, it results in being determinedthat the number of the elements of the already sorted frequency list islarger than the number of the elements of the already sorted datarelaying device list.

When the number of the elements of the already sorted frequency list isless than the number of the elements of the already sorted data relayingdevice list in the step A6 (no of the step A6), the symbol aggregationclustering unit 54 divides the total value (i.e. the total number of thetransfer-target symbols) of the frequencies within the process-targetdata relaying device element by a sum of the total numbers of thefrequencies within all elements of the already sorted data relayingdevice list (i.e. a sum of the total numbers of the transfer-targetsymbols), and obtains a value of its division result (this value isreferred to as an allotment ratio) (step A7).

After the step A7, the symbol aggregation clustering unit 54 divides“the total value of the communication speed and the processing speed”within the process-target data relaying device element by a sum of “thetotal values of the communication speeds and the processing speeds”within all elements of the already sorted data relaying device list, andobtains a value of its division result (this value is referred to as aspeed ratio) (step A8).

After the step A8, the symbol aggregation clustering unit 54 determineswhether or not the allocation ratio is less than the speed ratio (stepA9).

When the allocation ratio is less than the speed ratio in the step A9(yes of the step A9), the symbol aggregation clustering unit 54 adds“the symbol” being contained in the process-target frequency element to“the symbol aggregation” that corresponds to the data relaying deviceidentification information within the process-target data relayingdevice element in the symbol cluster information. In addition, thesymbol aggregation clustering unit 54 adds the value of the frequencybeing contained in the process-target frequency element to the totalnumber of the transfer-target symbols within the process-target datarelaying device element (step A10).

Further, when the allocation ratio is equal to or more than the speedratio in the step A9 (no of the step A9), the symbol aggregationclustering unit 54 proceeds to the step A5, and repeats the process ofthe step A5 and the steps subsequent hereto.

Further, after the step A10, the symbol aggregation clustering unit 54investigates the number of the elements of the already sorted frequencylist, and determines whether or not the rank of the process-targetfrequency element is the last rank of the already sorted frequency list(step A11). When the rank of the process-target frequency element is thelast rank (i.e. the lowest-place rank) of the already sorted frequencylist (yes of the step A11), the process is finished.

When the rank of the process-target frequency element is not the lastrank of the already sorted frequency list (no of the step A11), thesymbol aggregation clustering unit 54 acquires the element of the rankobtained by adding 1 (one) to the rank of the process-target frequencyelement recently acquired (the rank that is by one lower than that ofthe process-target frequency element recently acquired), and defines theabove element to be a process-target frequency element (step A12). Afterthe step A12, the symbol aggregation clustering unit 54 proceeds to thestep A5, and repeats the process of the step A5 and the steps subsequenthereto.

The symbol cluster information is obtained by performing the processshown in FIG. 18 hierarch by hierarchy.

Performing an operation of the step A1 to A12 allows a plurality of thesymbols sectioned by the inflection point in the already sortedfrequency list to be equally transferred to the data relaying device. Asa result, a deviation in the frequency table of the symbol thatcorresponds to the codes being transferred to the data relaying devicebecomes larger as compare with a deviation in the already sortedfrequency list because the total number of the frequencies is decreasedwhile a tendency of an increase in the frequency attended by a rise inthe rank in the already sorted frequency list is maintained. Further,performing an operation of the step A1 to A12 allows the symbol clusterinformation to be generated so that a magnitude relation of the totalnumber of the codes being transferred to the data relaying devicebetween the data relaying devices coincides with a magnitude relation ofthe total value of the communication speed and the processing speed ofthe data relaying device, thereby enabling a deviation of the processingloads imposed upon the data relaying devices of the identical hierarchynumber to be alleviated.

With the operation above, the symbol cluster information satisfying thefirst condition and the second condition already explained is generated,and the symbol cluster information generation of the step S404 iscompleted.

Further, omitting an operation of the foregoing step A6 allows a ratioof the frequency of the symbol being transferred to the data relayingdevice to come close to a ratio of the total value of the communicationspeed and the processing speed of the data relaying device, therebymaking it possible to give the processing speed precedence over thecompression ratio.

After the step S404, the symbol aggregation clustering unit 54 sends thesymbol cluster information to the transfer destination informationgenerating unit 55, and the transfer destination information generatingunit 55 acquires the above symbol cluster information (step S405).Further, the transfer destination information generating unit 55 loadsthe data relaying device information from the data relaying deviceinformation recording unit 56 (step S406). Next, the transferdestination information generating unit 55 converts the data relayingdevice identification information within the symbol cluster informationacquired in the step S405 into the destination information caused tocorrespond to the identical data relaying device identificationinformation within the data relaying device information acquired in thestep S406, and divides it hierarchy number by hierarchy number, therebyto generate the transfer destination information in which thedestination information of the upper-place data relaying device, out ofthe data relaying devices of each hierarchy, and the aggregation of thesymbols being transmitted to the upper-place data relaying device havebeen caused to correspond to each other (step S407).

Finally, the transfer destination information generating unit 55transmits the transfer destination information associated with theupper-place data relaying device groups to a plurality of the datarelaying device groups constituting each hierarchy by employing thecommunicating unit 51 (step S408). Next, the communicating unit 41 ofeach data relaying device receives the transfer destination informationtransmitted in the step S408, and, for example, the CPU of each datarelaying device causes the transfer destination information recordingunit 45 to store the above transfer destination information.

In the explanation above, the case that the data compressing devices 1to N5 were devices different from the data generating devices 1′ to N5′,respectively, was exemplified; however the data generating units 1′ toN5′ may be configured to have a function similar to the function of thedata compressing devices 1 to N5, respectively.

Next, an effect of the present invention will be explained. In thepresent invention, the data compressing devices 1 to N5 are independentof the data relaying device 3,1 to the data relaying device 3,5 each ofwhich has the largest hierarchy number, and further, one datacompressing device is used for each of the data generating devices 1′ toN5′, whereby the compressing process time of the data generated by thedata generating devices 1′ to N5′ is not increased even though a largenumber of the data generating devices exit.

Further, in the present invention, when recompressing the code beingcontained in the already compressed data, the data recompressing unit 44converts the codes into the other codes based upon the data analysisresult being contained in the already compressed data so as torecompress the data without converting the code into the symbol andrecompressing the above symbol. Further, the new data conversioninformation indicative of a correspondence between theafter-recompression code and the original symbol is prepared. Thus, theprocess of recompressing the data being collected can be performed at ahigh speed.

Further, in the present invention, when the already compressed data istransferred to the upper-place data relaying devices, the alreadycompressed data is transferred to the data relaying device thatcorresponds to the symbol being converted from the code. At this time,the data relaying device, being a transfer destination, is decided byemploying the transfer destination information derived based upon thesymbol cluster information by the transfer destination informationupdating device. Thus, the communication amount at the time that thedata collecting device 7 collects the data can be suppressed to a lowlevel, and the data collection speed can be raised.

That is, the symbol aggregation clustering unit 54 (see FIG. 7)generates the symbol cluster information so that the data amount beingtransferred to the data relaying device is regulated responding to thecommunication speed and the processing speed of the data relayingdevice. At this time, the symbol cluster information is generated sothat the appearance frequency of the specific bit string within the databeing transferred to the data relaying device becomes numerous. And, thedata compressed at a high speed, as described above, is transmitted tothe upper-place data relaying devices based upon the transferdestination information generated by the transfer destinationinformation updating device 5. Thus, the communication amount that isrequired at the moment of collecting the data from a plurality of theappliances can be reduced, and further, it can be realized that thespeed of the recompressing process for furthermore recompressing thecompressed data being collected is also made fast.

The data collecting device 7 for collecting the data includes the dataanalysis result acquiring unit 13 for acquiring the data analysis resultobtained in the compressing process at the moment of compressing thecollected already-compressed data, the basic symbol description formatrecording unit 15 for recording different description formats for theidentical bit string in the already compressed data, and the derivativesymbol description format recording unit 17 for recording a set of thederivative symbol that is configured of the identical bit string in thealready compressed data, and a plurality of the symbols constituting thederivative symbol. The data collecting device 7 configured in such amanner performs the process such as the statistical operation for thebit string by employing the data analysis result generated at the timeof compressing the data without expanding the collectedalready-compressed data for the time being, and then performing theoperating process, thereby making it possible to quicken the operatingspeed of the derivation of the statistical value (for example, thefrequency table) that the data collecting device carries out.

An example of the alteration to the above-mentioned embodiment will beexplained below.

The data relaying devices of the lowest-place hierarchy (the datarelaying device 3,1 to the data relaying device 3.5 in an example shownin FIG. 1) may be configured to include the data compressing devices 1to N5. Such a configuration enables a rise in the cost attended by anincrease in the number of the data generating devices to be suppressedbecause even though the number of the data generating devices isincreased, there is no necessity for increasing the data compressingdevise for performing the compressing process in line with the aboveincrease.

Further, the data collection system may be configured to include aplurality of the transfer destination information updating devices 5.For example, it may include the transfer destination informationupdating devices 5 for each hierarchy of the data relaying device. Sucha configuration enables the processing load imposed upon the transferdestination information updating device 5 to be dispersed.

Example 1

Hereinafter, an example of the present invention will be explained bymaking a reference to the accompanied drawings.

In this example, the data collection system includes an RFID reader asthe data generating devices 1′ to N5′, and includes a personal computeras the data compressing devices 1 to N5, the data collecting device 7,the data relaying devices (the data relaying device 1,1 to the datarelaying device K,J), and the transfer destination information updatingdevice 5. The RFID reader, being the data generating device, isconnected to the data compressing devices 1 to N5 through a serial cableetc. Each of the data compressing device 1 to N5, the data relayingdevices (the data relaying device 1,1 to the data relaying device K,J),the transfer destination information updating device 5, and the datacollecting device 7 is connected to LAN by Ethernet, and makescommunication by TCP/IP. Ethernet is a registration trademark.

The personal computer, being the data compressing device, includes anEthernet card that functions as the communicating unit 31, a magneticdisc device that functions as the received data recording unit 34 andthe symbol dictionary recording unit 33, and a central processing device(CPU) that functions as the data compressing unit 32.

The personal computer, being the data relaying device, includes anEthernet card that functions as the communicating unit 41, a magneticdisc device that functions as the received data recording unit 42, thetransfer destination information recording unit 45, the alreadycompressed data recording unit 441, and the execution history recordingunit 471, and a central processing device that functions as the symbolclassifying unit 43, the transfer destination deciding unit 46, the dataanalysis result acquiring unit 442, the data analysis resultsynthesizing unit 443, the data conversion information acquiring unit444, the data conversion information preparing unit 445, the dataconverting unit 446, the distance parameter computing unit 472, and thecompression information acquiring unit 473.

The personal computer, being the transfer destination informationupdating device 5, includes an Ethernet card that functions as acommunicating unit 51, a magnetic disc device that functions as the datarelaying device information recording unit 56, and a central processingdevice that functions as the distance parameter acquiring unit 52, thesymbol distribution generating unit 53, the symbol aggregationclustering unit 54, and the transfer destination information generatingunit 55.

The personal computer, being the data collecting device 7, includes anEthernet card that functions as the communicating unit 11, a magneticdisc device that functions as the received data recording unit 12, thebasic symbol description format recording unit 15, the derivative symboldescription format recording unit 17, and the operation result recordingunit 18, and a central processing device that functions as the dataanalysis result acquiring unit 13, the code operating unit 14, and thecode operation developing unit 16.

Hereinafter, the case that the data relaying device 3,1 shown in FIG. 1receives the already compressed data from the low-place device (hereinthe data compressing device 1 to N1) is exemplified for explanation.

FIG. 24 shows an example of the data being generated by each datagenerating device. In this example, the data that each of the datagenerating devices 1′ to N5′ generates is configured of the bit stringthat is comprised of 0 and 1 as shown in FIG. 24. In an example shown inFIG. 24, three symbols, i.e. “0000”, “1111”, and “0110” are contained.After each data compressing device acquires the data as exemplified inFIG. 24 from the data generating device, it performs the compressingprocess. FIG. 25 is an explanatory view illustrating an example of thedictionary data being stored by the magnetic storing device thatfunctions as the symbol dictionary recording unit 33 of the datacompressing device. In an example shown in FIG. 25, five bit string,i.e. “0000”, “1111”, “0110”, and “1001”, and “00001111” have beendecided. Further, in this example, the case that the data compressingdevice derives the frequency table of the symbol as a data analyzingprocess of the compressing process, and performs the Huffman codingprocess as a data converting process is exemplified. The dictionary dataexemplified in FIG. 25 has decided that the frequency (the number oftimes of the appearances) is obtained for the above-mentioned five bitstrings (symbols), and the Huffman code is derived, thereby to make aconversion to the code.

FIG. 26 shows an example of the data analysis result and the dataconversion information in this example. The data compressing unit 32(the central processing device of the data compressing device) countsthe number of times of the appearances (appearance frequency) of eachsymbol decided within the dictionary data, which exists within the datagenerated by the generating device, and obtains the by-symbol number oftimes of the appearances as a frequency table. FIG. 26( b) is an exampleof the frequency table that is obtained as a result.

Next, the data compressing unit 32 performs the Huffman coding processbased upon the number of times of the appearances of each symbol thatthe above frequency table indicates, and derives the Huffman code ofeach symbol. And, it generates the information in which the symbol andthe Huffman code have been caused to correspond to each other symbol bysymbol as data conversion information. And, the data compressing unit 32replaces the symbol being contained in the bit string generated by thedata generating device with the code corresponding to the symbol(herein, the Huffman code) based upon the data conversion information,and derives code data exemplified in FIG. 26( a). In an example of thecode data shown in FIG. 26( a), the code of which the code number goesas far as three is shown. The data compressing unit 32 replaces thesymbol with the code in such a manner so as to compresses the data.

The data compressing unit 32 generates the data analysis result, thedata conversion information, and the code data as exemplified in FIG.26. The data compressing unit 32 generates the already compressed datacontaining the code data, the data analysis result, and the dataconversion information, and transmits it to the data relaying device viathe communicating unit 31. Additionally, the data compressing unit 32may cause the already compressed data to contain information of thetotal number of the codes. FIG. 27 is an explanatory view illustratingan example of the data analysis result and the data conversioninformation generated by a plurality of the data compressing devices. Itis assumed that the data compressing device 1 has generated the dataanalysis result and the data conversion information exemplified in FIG.27( a). Hereinafter, these data analysis result and data conversioninformation are referred to as a data analysis result A1, and a dataconversion information A1, respectively. Further, it is assumed that thedata compressing device 2 has generated the data analysis result and thedata conversion information exemplified in FIG. 27( b). Hereinafter,these data analysis result and data conversion information are referredto as a data analysis result A2, and a data conversion information A2,respectively.

Next, it is assumed that the personal computer, being the data relayingdevice in this example, receives the data analysis result A1, the dataconversion information A1, and the code data as shown in FIG. 27( a)from the data compressing device 1 as the already compressed data, andlikewise, receives the data analysis result A2, the data conversioninformation A2, and the code data as shown in FIG. 27( b) from the datacompressing device 2.

It is assumed that the transfer destination information (the hierarchynumber 3) shown in FIG. 28 has been recorded as transfer destinationinformation in the magnetic disc device (the transfer destinationinformation recording unit 45) within the personal computer, being thedata relaying device in this example. However, in this example, it isassumed that the hierarchy of the data relaying device is the hierarchy3, and the data relaying device having the hierarchy number 1 has storedthe transfer destination information exemplified in FIG. 28( a).Likewise, it is assumed that the data relaying devices having thehierarchy number 2 and the hierarchy number 3 have stored the transferdestination information exemplified in FIG. 28( b) and in FIG. 28( c),respectively. Herein, for explanation, attention is paid to the datarelaying device 3,1 storing the transfer destination informationexemplified in FIG. 28( c).

Each symbol equivalent to the symbol aggregation is shown in a column ofthe symbol aggregation of each of the transfer destination information(the hierarchy number 1), the transfer destination information (thehierarchy number 2), and the transfer destination information (thehierarchy number 3) shown in FIG. 28. Further, the information in whichthe destination IP address and the destination port number have beencoupled by means of the character of “:”, being information of thedestination to which the already compressed data of each symbol of thesymbol aggregation is transferred, is shown in a column of the datarelaying device destination information thereof.

The magnetic storing device (the received data recording unit 42) withinthe personal computer, being the data relaying device in this example(herein, the case of the hierarchy number 3 is exemplified), stores thealready compressed data received from a plurality of the datacompressing devices.

Next, the central processing device within the personal computer, beingthe data relaying device in this example, converts the codes within thealready compressed data into the symbols by employing the dataconversion information within the already compressed data recorded bythe above magnetic storing device. Next, the central processing deviceof the data relaying device having the hierarchy number 3 extracts thesymbols of “0000”, “1111”, and “00001111” as a symbol aggregation A, thesymbol of “0110” as a symbol aggregation B, and the symbol of “1001” asa symbol aggregation C by making a reference to the transfer destinationinformation shown in FIG. 28( c).

In this extraction operation, for example, performing only thedetermining process of the symbol “0110” and the symbol “1001” for thebit string within the data, and classifying the symbol, which is notdecided to be “0110” or “1001”, into the symbol aggregation A, makes itpossible to execute the extraction operation at higher speed as comparedwith the case of classifying the symbol one by one. That is, in theascending order of number of the symbols belonging to the symbolaggregation, specifying the symbols (symbols converted from the codes)belonging to the above symbol aggregation allows the classification tobe carried out at a high speed.

With regard to the symbol aggregations A, B, and C, the code datacorresponding hereto within the already compressed data received fromthe data compressing device 1, and the code data corresponding heretowithin the already compressed data received from the data compressingdevice 2 are separately preserved within the magnetic storing devicethat operates as the already compressed data recording unit 441. Forexample, the code data corresponding to the symbol aggregation A withinthe already compressed data received from the data compressing device 1,and the code data corresponding to the symbol aggregation A within thealready compressed data received from the data compressing device 2 areseparately preserved. The situation of other symbol aggregations is alsosimilar.

Next, the central processing device of the data relaying device performsthe recompressing process symbol aggregation by symbol aggregation.Hereinafter, the details of the recompressing process will be explainedby exemplifying the case of the symbol aggregation A.

FIG. 29 is an explanatory view illustrating an example of generating onedata analysis result from a plurality of the data analysis results. Thecentral processing device of the data relaying device acquires aplurality of the data analysis results from a plurality of pieces of thealready compressed data as shown in FIG. 29, and generates one dataanalysis result. FIG. 29 shows the case of generating one data analysisresult from the two data analysis results within the already compresseddata. The central processing device of the data relaying device, foreach symbol of the symbol aggregation A being contained in two dataanalysis results A1 and A2, calculates a sum of the frequency (thenumber of times of the appearances) of the above symbol. Specifically,it obtains a sum of the frequency of “0000” being contained in two dataanalysis results A1 and A2, and further, likewise, obtains a sum of thefrequency, with regard to the other symbols “1111” and “00001111” aswell belonging to the symbol aggregation A similarly to the above case,respectively. In such a manner, it derives one data analysis result A3shown in FIG. 29.

And, the central processing device of the data relaying device performsthe Huffman coding for each symbol (each symbol of the symbolaggregation A), and generates the data conversion information in whicheach symbol and the Huffman code have been caused to correspond eachother from the data analysis result A3 shown in FIG. 29 as an operationequivalent to the data conversion information preparing unit 445. Anexample of the data conversion information A3 derived from the dataanalysis result A3 by performing the Huffman coding is shown in FIG. 30.Next, the above central processing device converts the code data withinthe already compressed data received from the devices that rank lower byone hierarchy into another code data shown in the new data conversioninformation by employing the data conversion information A1 and the dataconversion information A3 as an operation equivalent to the dataconverting unit 446. In this example, the central processing deviceconverts a code “0110” (see the data conversion information A1 shown inFIG. 27) corresponding to the symbol “0000” of the symbol aggregation A,being code data within the already compressed data received from thedata compressing device 1, into a code “00” corresponding to “0000” inthe new data conversion information A3. Likewise, it converts a code “1”(see the data conversion information A1 shown in FIG. 27) correspondingto the symbol “1111” of the symbol aggregation A into a code “1”corresponding to “1111” in the new data conversion information A3.Likewise, it converts “0111” (see the data conversion information A1shown in FIG. 27) corresponding to the symbol “00001111” of the symbolaggregation A into a code “01” corresponding to “00001111” in the newdata conversion information A3.

Likewise, the central processing device of the data relaying deviceconverts the code data within the already compressed data received fromthe data compressing device 2 into another code data shown in the newdata conversion information by employing the data conversion informationA2 and the data conversion information A3 as an operation equivalent tothe data converting unit 446. In this example, the central processingdevice converts a code “1010” (see the data conversion information A2shown in FIG. 27) corresponding to the symbol “0000” of the symbolaggregation A, being code data within the already compressed datareceived from the data compressing device 2, into the code “00”corresponding to “0000” in the new data conversion information A3.Likewise, it converts “11” (see the data conversion information A2 shownin FIG. 27) corresponding to the symbol “1111” of the symbol aggregationA into the code “1” corresponding to “1111” in the new data conversioninformation A3. Likewise, it converts “1011 (see the data conversioninformation A2 shown in FIG. 27) corresponding to the symbol “00001111”of the symbol aggregation A into the code “01” corresponding to“00001111” in the new data conversion information A3.

The central processing device of the data relaying device performs thesimilar recompressing process for the symbol aggregations B and C aswell, respectively.

FIG. 31 is an explanatory view illustrating an example of therecompression relating to the symbol aggregations B and C. The centralprocessing device of the data relaying device, similarly to the case ofobtaining the data analysis result A3, derives one data analysis resultB3 from the data analysis results A1 and A3 by computing a sum of thefrequencies of the symbols belonging to the symbol aggregation B, andfurther, derives one data analysis result C3 from the data analysisresults A1 and A3 by computing a sum of the frequencies of the symbolsbelonging to the symbol aggregation C (see FIG. 31). In addition, it,similarly to the case of obtaining the data conversion information A3,derives data conversion information B3 and C3 from the data analysisresults B3 and C3, respectively (see FIG. 31).

Next, the central processing device of the data relaying device convertsthe code data within the already compressed data received from thedevices that rank lower by one hierarchy into another code data shown inthe new data conversion information by employing the data conversioninformation A1 and A2, and the data conversion information B3 as anoperation equivalent to the data converting unit 446, similarly to theoperation by the data converting unit 446 for the symbol aggregation A.In this example, the central processing device converts a code “010”corresponding to the symbol “0110” of the symbol aggregation B, beingcode data within the already compressed data received from the datacompressing device 1, into the code “0” corresponding to “0110” in thenew data conversion information B3 (see the data conversion informationA1 shown in FIG. 27 and the data conversion information B3 shown in FIG.31). Likewise, it converts a code “100” corresponding to the symbol“0110” of the symbol aggregation B, being code data within the alreadycompressed data received from the data compressing device 2, into thecode “0” corresponding to “0110” in the new data conversion informationB3 (see the data conversion information A2 shown in FIG. 27 and the dataconversion information B3 shown in FIG. 31).

Further, the central processing device of the data relaying deviceconverts the code data within the already compressed data received fromthe devices that rank lower by one hierarchy into another code datashown in the new data conversion information by employing the dataconversion information A1 and A2, and the data conversion information C3as an operation equivalent to the data converting unit 446, similarly tothe operation by the data converting unit 446 for the symbolaggregations A and B. In this example, the central processing deviceconverts the code “00” corresponding to the symbol “1001” of the symbolaggregation C, being code data within the already compressed datareceived from the data compressing device 1, into thea code “1”corresponding to “1001” in the new data conversion information C3.Further, it converts the code “0” corresponding to the symbol “1001” ofthe symbol aggregation C, being code data within the already compresseddata received from the data compressing device 2, into the code “1”corresponding to “1001” in the new data conversion information C3.

Next, the central processing device of the data relaying device makes areference to the transfer destination information (hierarchy number 3)shown in FIG. 28( c), and transmits the already compressed datagenerated in the recompressing process for the symbol aggregation A,being an operation equivalent to the data converting unit 446, to thedata relaying device of which the IP address and the port number are192.168.2.1 and 5060, respectively as an operation of the transferdestination deciding unit 46. Likewise, the central processing device ofthe data relaying device makes a reference to the transfer destinationinformation (hierarchy number 3) shown in FIG. 28( c), and transmits thealready compressed data generated in the recompressing process for thesymbol aggregation B, being an operation equivalent to the dataconverting unit 446, to the data relaying device of which the IP addressand the port number are 192.168.2.2 and 5060, respectively as anoperation of the transfer destination deciding unit 46. Likewise, thecentral processing device of the data relaying device transmits thealready compressed data generated in the recompressing process for thesymbol aggregation C to the data relaying device of which the IP addressand the port number are 192.168.2.3 and 5060, respectively.

The size of the code data within the already compressed data is computedwith the total sum of the length of the codes constituting the codedata. With the foregoing recompressing process, the size of the codedata within the already compressed data is changed from 470 to 255 withthe symbol aggregation A, from 90 to 40 with the symbol aggregation B,and from 240 to 160 with the symbol aggregation C, respectively, and thecommunication amount is reduced all the more as compared with the caseof communicating the already compressed data without recompressing it.

Further, the above-mentioned recompressing process is a process of,after expanding the already compressed data recorded in the alreadycompressed data recording unit 441, performing the data analysis and thedata conversion for the entirety of the after-expansion data, which isperformed by the symbol classifying unit 43. At this time, the dataanalysis result and the data conversion information of the symbol beingcontained in the before-compression already-compressed data, i.e. thedata equivalent to the original data, are generated from the dataanalysis result and the data conversion information of which the size issmaller that of the after-expansion data. Thus, the processing amount aswell required for curtailing the communication amount is curtailed ascompared with the case of generating the data analysis result and thedata conversion information of the symbol being contained in thebefore-compression already-compressed-data, i.e. the data equivalent tothe original data.

All data relaying devices in this example perform a process similar tothe process that the above-mentioned data relaying device 3,1 performs,and finally, the data relaying devices 1,1 and 1,2 make a reference tothe transfer destination information (hierarchy number 1) shown in FIG.28, and transmits the already compressed data, which has beenrecompressed symbol aggregation by symbol aggregation, to the personalcomputer, being the data collecting devoice 7. In this example, it isassumed that the data relaying device 1,1 and the data relaying device1,2 can the TCP/IP communication with the personal computer, being thedata collecting devoice 7, by employing the IP address “192.168.0.1 andthe port number “5060”.

Next, when the personal computer, being the data collecting device 7 inthis example, receives the already compressed data transmitted by thedata relaying device 1,1 and the data relaying device 1,2 by employingthe Ethernet device, being the communicating unit 11, it causes themagnetic storing device that functions as the received data recordingunit 12 to store the above already compressed data.

Next, the central processing device within the personal computer, beingthe data collecting devoice 7, acquires the data analysis result symbolaggregation by symbol aggregation from the already compressed datarecorded in the magnetic storing device as an operation equivalent tothe data analysis result acquiring unit 13.

An example of the data analysis result is shown in FIG. 32. An exampleshown in FIG. 32 shows that a data analysis result A4 has been obtainedfrom the already compressed data of the symbol aggregation A (see FIG.32( a)). Likewise, it shows that a data analysis result B4 has beenobtained from the already compressed data of the symbol aggregation B(see FIG. 32( b)). Further, it shows that a data analysis result C4 hasbeen obtained from the already compressed data of the symbol aggregationC (see FIG. 32( c)).

In this example, it is assumed that the symbol description informationas shown in FIG. 33 has been recorded within the magnetic storing devicewithin the personal computer, being the data collecting device 7, whichoperates as the basic symbol description format recording unit 15. Anexample of the symbol description information shown in FIG. 33 signifiesthat the symbol “0110” is listed as another symbol “1001”.

Further, in this example, the derivative symbol configurationinformation as shown in FIG. 34 has been recorded within the magneticstoring device within the personal computer, being the data collectingdevice 7, which operates as the derivative symbol description formatrecording unit 17. An example of the derivative symbol configurationinformation shown in FIG. 34 signifies that the symbol “00001111” isconfigured of two symbols, i.e. “0000” and “1111”.

Next, the central processing device of the data collecting device 7computes the statistical value relating to the symbol converted into thecode within the code data of the already compressed data from dataanalysis results A4, B4, and C4 shown in FIG. 32 as an operationequivalent to the code operating unit 14. In this example, the case ofgenerating a histogram (frequency table) as a statistical value will beexplained.

The central processing device of the data collecting device 7 firstlyacquires the total number of the symbols within the symbol aggregationsA, B, and C contained within the already compressed data from the dataanalysis results A4, B4, and C4 shown in FIG. 32. For example, the totalnumber of the symbol “0000” is frequency “200” of the symbol “0000” thatthe data analysis result A indicates, and the central processing deviceof the data collecting device 7 acquires this value.

The central processing device of the data collecting device 7 acquiresthe total number of the other symbols with the similar process, andgenerates the frequency table of the symbol being contained within thecollected data. A frequency table 1 of the symbol exemplified in FIG.35( a) signifies an example of the histogram (frequency table) generatedin such a manner. Additionally, FIG. 35 shows an example of thefrequency table being generated by the data collecting device 7.

Next, the central processing device of the data collecting device 7regards the total number of the symbol “1001” as the number of times ofthe appearances of the symbol “0110” and adds it to the total number ofthe symbol “0110” by employing the symbol description information shownin FIG. 33. A frequency table 2 of the symbol shown in FIG. 35( b)signifies an example of the frequency table obtained by the additionbased upon such symbol description information.

Next, the central processing device of the data collecting device 7makes a reference to the derivative symbol configuration informationexemplified in FIG. 34, regards the total number of the symbol“00001111” as the number of times of the appearances of the symbols“0000” and “1111”, and adds it to the total number of the symbol “0000”and the total number of the symbol “1111”, respectively, as an operationequivalent to the code operation developing unit 16. That is, it regardsthe number of times of the appearances of the derivative symbol as thenumber of times of the appearances of each symbol being contained in thedescription format of the derivative symbol, and adds it to the numberof the symbols being contained in the description format of thederivative symbol. A frequency table 3 of the symbol shown in FIG. 35(c) signifies an example of the frequency table obtained by the additionbased upon such derivative symbol configuration information. The centralprocessing device of the data collecting device 7 finally generates thehistogram exemplified in FIG. 36, and records it in the magnetic storingdevice that functions as the operation result recording unit 18.

With the operation above, the personal computer, being the datacollecting device 7 in this example, obtains a histogram 3 (thefrequency table 3 of the symbol) exemplified in FIG. 35( c), being ahistogram of the symbol being contained within the data generated fromthe RFID reader, being a data generating device. This operation isperformed by the data analysis result acquiring unit 13, the codeoperating unit 14, and the code operation developing unit 16 each ofwhich performs an arithmetic operation by employing the data analysisresult of which the size is smaller than that of the after-expansiondata. Thus, the processing amount of the central processing device canbe curtailed as compared with the case of generating the frequency table3 of the symbol by expanding the collected already-compressed data, andthereafter, summing up the total number of the symbols.

Next, an operation of the symbol aggregation clustering informationacquiring unit 47, which is performed by the central processing devicewithin the personal computer, being the data relaying device in thisexample, and an operation of the personal computer, being the transferdestination information updating device 5, will be explained by making areference to FIG. 37 and FIG. 38.

The execution history information, which is configured of thecommunication speed of the already compressed data transferred by thetransfer destination deciding unit 46, the time required for therecompressing process by the data recompressing unit 44, the size of thealready compressed data generated by the recompressing process, the dataanalysis result of the already compressed data, and the data conversioninformation, has been recorded in the magnetic storing device within thepersonal computer that operates as the data relaying device, whichoperates as the execution history recording unit 471.

FIG. 37 is an explanatory view illustrating an example of the executionhistory information. An example shown in FIG. 37 signifies that, whenthe central processing device of the data relaying device including themagnetic storing device in which the execution history information shownin FIG. 37 was recorded generated the already compressed data of whichthe size was 8,000 kilobits, the time required for the recompressingprocess was 50 milliseconds, a data analysis result 131 was generated,and the communication speed at the moment of transmitting it to theupper-place data relaying device was 50 Mbps. Further, it signifies thatthe data relaying device identification information of the above datarelaying device is “3,1”, and the hierarchy number is “3”.

The central processing device within the personal computer, being thedata relaying device in this example, acquires the communication speed“50 (Mbps)” from the execution history information as an operation ofthe distance parameter computing unit 472. Further, it also acquires thealready compressed data size “8,000 (Kbits), and the recompressingprocess time “50 (ms)” from the execution history information, andcalculates “160 (Mbps)”, being a value obtained by dividing the abovedata size “8,000 (Kbits) by the recompressing process time “50 (ms)”, asa processing speed. And, it transmits the above-mentioned communicationspeed “50 (Mbps)” and processing speed “160 (Mbps)”, and data relayingdevice identification information “3,1” and hierarchy number “3” to thepersonal computer, being the transfer destination information updatingdevice 5 in this example, by employing the Ethernet device within thepersonal computer (data relaying device) including the above centralprocessing device.

Next, the central processing device within the personal computer, beingthe data relaying device in this example, acquires the data analysisresult 131 (see FIG. 37) recorded in the execution history recordingunit 471 as an operation of the compression information acquiring unit473. Further, when generating the information other than the frequencytable as a data analysis result, the central processing device of thedata relaying device generates a frequency table 4 of the symbol asshown in FIG. 38 with a method similar to the method of generating thefrequency table 1 of the symbol exemplified in FIG. 35( a). And, thecentral processing device of the data relaying device employs theEthernet device within the personal computer (data relaying device)including the above central processing device, and transmits the abovefrequency table 4 of the symbol (see FIG. 38) to the personal computer,being the transfer destination information updating device 5 in thisexample. With an example of the execution history information shown inFIG. 37, the data analysis result 131 can be employed as the frequencytable 4 shown in FIG. 38 as it stands because the frequency table isgenerated as a data analysis result in this example.

Next, the central processing device within the personal computer, beingthe transfer destination information updating device 5 in this example,receives the communication speed, the processing speed, the datarelaying device identification information, and the hierarchy numberthat are transmitted from the data relaying device, by employing theEthernet device that functions as the communicating unit 51 as anoperation of the distance parameter acquiring unit 52. FIG. 39 is anexplanatory view illustrating an example of the communication speed, theprocessing speed, the hierarchy number, and the data relaying deviceidentification information that the transfer destination informationupdating device 5 receives. For example, the information exemplified inthe first line of FIG. 39 signifies that the communication speed and theprocessing speed acquired from the data relaying device of which thehierarchy number and the data relaying device identification informationare 2, and 2,1, respectively, are 50 and 160, respectively.

Further, the central processing device of the transfer destinationinformation updating device 5 receives a frequency table 4 (see FIG. 38)of the symbol by employing the Ethernet device that functions as thecommunicating unit 51, and generates the frequency table in which thenumber obtained by adding the frequency of the symbol within eachfrequency table is defined as a new total number of the symbols from theother frequency tables received within the past constant time, and thefrequency table 4 of the symbol as an operation of the symboldistribution generating unit 53. An example of the frequency table ofthe symbol obtained by adding the total of the by-symbol number of timesof the appearances in such a manner is exemplified in FIG. 40. However,as already explained, when the frequency table is contained in theexecution history information as a data analysis result, the centralprocessing device of the transfer destination information updatingdevice 5 receives the above frequency table.

Next, the central processing device of the transfer destinationinformation updating device 5 generates the symbol cluster informationby performing the following operation as an operation of the symbolaggregation clustering unit 54. The central processing device sorts acombination of the symbol and the frequency of the above symbol in thedescending order of the frequency in the frequency table exemplified inthe frequency table (FIG. 40) generated as mentioned above, andgenerates the already sorted frequency list exemplified in FIG. 19.

In addition, the central processing device that operates as the symbolaggregation clustering unit 54 extracts the data relaying deviceidentification information of the data relaying devices to which theidentical hierarchy number has been allotted from the receivedcommunication speed, processing speed, hierarchy number, and datarelaying device identification information exemplified in FIG. 39, andgenerates the information in which the data relaying deviceidentification information has been listed hierarchy by hierarchy. Inaddition, it generates the information in which the listed data relayingdevice identification information, and the total value of thecommunication speed and the processing speed corresponding to the datarelaying device identification information, and the total number of thetransfer-target symbols have been caused to correspond to each other,and sorts a combination of the data relaying device identificationinformation, the total value of the communication speed and theprocessing speed, and the total number of transfer-target symbols in thedescending order of the total value of the communication speed and theprocessing speed. And, it affixes an after-sorting rank to each of thesecombinations, thereby to prepare the already sorted data relaying devicelist. For example, the already sorted data relaying device listexemplified in FIG. 20 is generated based upon the informationexemplified in FIG. 39.

In addition, the central processing device subtracts the frequency ofthe symbol of which the rank is an n-th place from the frequency of thesymbol of which the rank is an (n+1)-th place in the already sortedfrequency list, and decides the rank of the first-order differentialvalue, being its subtraction result, to be an n-th place. It continuesthis process in the order of n=1, 2, . . . until the process of thesubtraction is completed thereby to generate the first-orderdifferential value list exemplified in FIG. 21.

In addition, the central processing device subtracts the first-orderdifferential value of which the rank is an n-th place from thefirst-order differential value of which the rank is an (n+1)-th place inthe first-order differential list, and decides the rank of thesecond-order differential value, being its subtraction result, to be ann-th place. It continues this process in the order of n=1, 2, . . .until the process of the subtraction is completed thereby to generatethe second-order differential value list exemplified in FIG. 22.

And, when a mark of the second-order differential value in thesecond-order differential value list has been changed from that of thesecond-order differential value that ranks higher by one, the centralprocessing device extracts the rank of the second-order differentialvalue of which the mark has been changed. The central processing deviceperforms this extraction operation in the order of the rank in thesecond-order differential value list and decides new rank for theextracted rank in the order of extraction. With this operation, theinflection point list as exemplified in FIG. 23 is derived.

An operation of the steps A1 to A12 shown in FIG. 18 is performed byemploying the already sorted frequency list (see FIG. 19), the alreadysorted data relaying device (see FIG. 20), and the inflection point list(see FIG. 23) derived above. Performing the above operation hierarch byhierarchy allows the symbol cluster information to be generated.

An example of the symbol cluster information being obtained with theabove operation is shown in FIG. 41.

The data relaying device information has been recorded in the magneticstoring device that operates as the data relaying device informationrecording unit 56 within the personal computer, being the transferdestination information updating device 5 in this example. FIG. 42 is anexplanatory view illustrating an example of the data relaying deviceinformation stored in the transfer destination information updatingdevice 5. In the data relaying device information shown in FIG. 42, thehierarch number 0 signifies the data collecting device 7. For example,the second line of the table shown in FIG. 42 signifies that thepersonal computer, being the data relaying device having the hierarchnumber 1 to which the data relaying device identification information“1,1” has been allotted, can the TCP/IP communication by employing thedestination IP address 192.168.1.1 and the port number 5060. In FIG. 42,the destination information is signified with the character string inwhich the IP address and the port number have been coupled by means ofthe letter of “:”

The central processing device of the transfer destination informationupdating device 5 converts the data relaying device identificationinformation being contained in the symbol cluster information shown inFIG. 41 into the destination information caused to correspond to theidentical data relaying device identification information in the datarelaying device information shown in FIG. 42, and divides it for eachhierarchy number, thereby to generate the transfer destinationinformation shown in FIG. 28 as an operation equivalent to the transferdestination information generating unit 55.

Next, the central processing device of the transfer destinationinformation updating device 5 acquires the destination information ofthe data relaying devices of each hierarch number from the data relayingdevice information shown in FIG. 42, and transmits theby-hierarchy-number transfer destination information shown in FIG. 28 toall of the data relaying devices of which a hierarchy number identicalto the above hierarchy number has been allotted by employing theEthernet device within the personal computer, being the transferdestination information updating device 5, as an operation equivalent tothe transfer destination information generating unit 55. For example,the central processing device of the transfer destination informationupdating device 5 makes a reference to the destination information ofthe data relaying devices of which the hierarch number is 3 within thedata relaying device information of FIG. 42, and transmits the transferdestination information (hierarch number 3) of FIG. 42 by use of theTCP/IP to the personal computer that operates as the data relayingdevices of which the destination IP address and the destination portnumber are “192.168.3.1” and “5060”, “192.168.3.2” and “5060”,“192.168.3.3” and “5060”, “192.168.3.4” and “5060”, and “192.168.3.5”and “5060”, respectively, by employing the Ethernet device.

In the above-mentioned example, the case of recording the data relayingdevice identification information in the execution history recordingunit 471 of each data relaying device, and the data relaying deviceinformation recording unit 56 within the transfer destinationinformation updating device 5 was explained; however the data relayingdevice identification information can be managed by employing a namesolving method such as DNS (Domain Name Service).

The present invention described above is preferredly applicable to thedata collection system for collecting the data via the communicationnetwork.

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2007-047118, filed on Feb. 27, 2007, thedisclosure of which is incorporated herein in its entirety by reference.

1. A data collection system comprising a plurality of data compressingdevices for compressing data, a plurality of data relaying devices forrelaying the data, and a data collecting device for collecting the data,said plurality of said data relaying devices being arranged hierarchy byhierarchy responding to the number of hops or a round trip time up tothe data collecting device so that the smaller the number of the hops orthe round trip time of the data relaying device up to the datacollecting device is, the higher the hierarchy of the data relayingdevice becomes, said data collecting device receiving already compresseddata containing a data analysis result, being an analysis result of astatistical special feature of the data that is a target of compression,a code that is decided for a symbol, being a before-compression bitstring, responding to the analysis result, and data conversioninformation indicative of a correspondence between the symbol and thecode from each relaying device of a highest-place hierarchy, wherein thedata collecting device comprises: a basic symbol description formatrecording means for storing symbol description information in which abasic symbol, being a symbol divided into a minimum unit, and adescription format in which the basic symbol has been expressed withother formats have been caused to correspond to each other; a derivativesymbol format recording means for storing information in which aderivative symbol, being a symbol in which the basic symbols have beencombined, and an aggregation of the basic symbols constituting thederivative symbol have been caused to correspond to each other; a codeoperating means for deriving a frequency of the symbol for each symbolcorresponding to the code being contained in the already compressed databased upon the data analysis result being contained in the receivedalready compressed data; and a code operation developing means foradding the frequency of the description format, out of the frequenciesobtained by the code operating means, to the frequency of the basicsymbol corresponding to the above description format, and adding thefrequency of the derivative symbol to the frequency of each basic symbolconstituting the derivative symbol.
 2. A data collection method that isapplied for a data collection system comprising a plurality of datacompressing devices for compressing data, a data collecting device forcollecting the data, and data relaying devices being arranged hierarchyby hierarchy responding to the number of hops or a round trip time up tothe data collecting device so that the smaller the number of the hops orthe round trip time of the data relaying device up to the datacollecting device is, the higher the hierarchy of the data relayingdevice becomes, said data collecting device receiving already compresseddata containing a data analysis result, being an analysis result of astatistical special feature of the data that is a target of compression,a code that is decided for a symbol, being a before-compression bitstring, responding to the analysis result, and data conversioninformation indicative of a correspondence between the symbol and thecode from each relaying device of a highest-place hierarchy: wherein thedata collecting device stores symbol description information in which abasic symbol, being a symbol divided into a minimum unit, and adescription format in which the basic symbol has been expressed withother formats have been caused to correspond to each other; wherein thedata collecting device stores information in which a derivative symbol,being a symbol in which the basic symbols have been combined, and anaggregation of the basic symbols constituting the derivative symbol havebeen caused to correspond to each other; wherein the data collectingdevice derives a frequency of the symbol for each symbol correspondingto the code being contained in the already compressed data, based uponthe data analysis result being contained in the received alreadycompressed data; and wherein the data collecting device adds thefrequency of the description format, out of the frequencies, to thefrequency of the basic symbol corresponding to the above descriptionformat, and adds the frequency of the derivative symbol to the frequencyof each basic symbol constituting the derivative symbol.
 3. A datacollecting device for collecting already compressed data containing adata analysis result, being an analysis result of a statistical specialfeature of data that is a target of compression, a code that is decidedfor a symbol, being a before-compression bit string, responding to theanalysis result, and data conversion information indicative of acorrespondence between the symbol and the code, said data collectingdevice comprising: a basic symbol description format recording means forstoring symbol description information in which a basic symbol, being asymbol divided into a minimum unit, and a description format in whichthe basic symbol has been expressed with other formats have been causedto correspond to each other; a derivative symbol format recording meansfor storing information in which a derivative symbol, being a symbol inwhich the basic symbols have been combined, and an aggregation of thebasic symbols constituting the derivative symbol have been caused tocorrespond to each other; a code operating means for deriving afrequency of the symbol for each symbol corresponding to the code beingcontained in the already compressed data based upon the data analysisresult being contained in the received already compressed data; and acode operation developing means for adding the frequency of thedescription format, out of the frequencies obtained by the codeoperating means, to the frequency of the basic symbol corresponding tothe above description format, and adding the frequency of the derivativesymbol to the frequency of each basic symbol constituting the derivativesymbol.
 4. A data collection program causing a computer comprising: abasic symbol description format recording means for collecting alreadycompressed data containing a data analysis result, being an analysisresult of a statistical special feature of data that is a target ofcompression, a code that is decided for a symbol, being abefore-compression bit string, responding to the analysis result, anddata conversion information indicative of a correspondence between thesymbol and the code, and storing symbol description information in whicha basic symbol, being a symbol divided into a minimum unit, and adescription format in which the basic symbol has been expressed withother formats have been caused to correspond to each other; and aderivative symbol format recording means for storing information inwhich a derivative symbol, being a symbol in which the basic symbolshave been combined, and an aggregation of the basic symbols constitutingthe derivative symbol have been caused to correspond to each other toexecute: a code operating process of deriving a frequency of the symbolfor each symbol corresponding to the code being contained in the alreadycompressed data, based upon the data analysis result being contained inthe received already compressed data; and a code operation developingprocess of adding the frequency of the description format, out of thefrequencies obtained in the code operating process, to the frequency ofthe basic symbol corresponding to the above description format, andadding the frequency of the derivative symbol to the frequency of eachbasic symbol constituting the derivative symbol.